Document and Entity Information
Document and Entity Information - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Mar. 14, 2019 | Jun. 29, 2018 | |
Document And Entity Information [Abstract] | |||
Document Type | 10-K | ||
Amendment Flag | false | ||
Document Period End Date | Dec. 31, 2018 | ||
Document Fiscal Year Focus | 2018 | ||
Document Fiscal Period Focus | FY | ||
Trading Symbol | TBIO | ||
Entity Registrant Name | Translate Bio, Inc. | ||
Entity Central Index Key | 0001693415 | ||
Current Fiscal Year End Date | --12-31 | ||
Entity Filer Category | Non-accelerated Filer | ||
Entity Current Reporting Status | Yes | ||
Entity Well-known Seasoned Issuer | No | ||
Entity Voluntary Filers | No | ||
Entity Small Business | true | ||
Entity Emerging Growth Company | true | ||
Entity Ex Transition Period | true | ||
Entity Shell Company | false | ||
Entity Common Stock, Shares Outstanding | 45,273,722 | ||
Entity Public Float | $ 215,756,427 |
Condensed Consolidated Balance
Condensed Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Current assets: | ||
Cash and cash equivalents | $ 55,199 | $ 48,058 |
Short-term investments | 88,904 | 9,997 |
Prepaid expenses and other current assets | 4,474 | 3,014 |
Restricted cash | 1,025 | 1,966 |
Total current assets | 149,602 | 63,035 |
Property and equipment, net | 10,245 | 6,778 |
Goodwill | 21,359 | 21,359 |
Intangible assets, net | 106,445 | 106,842 |
Deferred offering costs | 511 | |
Other assets | 22 | |
Total assets | 287,651 | 198,547 |
Current liabilities: | ||
Accounts payable | 5,168 | 4,594 |
Accrued expenses | 6,547 | 5,888 |
Current portion of contingent consideration | 1,296 | |
Current portion of deferred revenue | 2,572 | |
Deferred rent | 307 | |
Total current liabilities | 14,287 | 12,085 |
Long-term portion of contingent consideration | 103,642 | 79,713 |
Deferred revenue, net of current portion | 41,841 | |
Deferred tax liabilities | 481 | 6,039 |
Deferred rent, net of current portion | 2,105 | 1,329 |
Total liabilities | 162,356 | 99,166 |
Commitments and contingencies (Notes 3, 4 and 14) | ||
Redeemable convertible preferred stock (Series A, B and C), $0.001 par value; no shares and 145,833,064 shares authorized as of December 31, 2018 and 2017, respectively; no shares and 142,288,292 shares issued and outstanding as of December 31, 2018 and 2017, respectively | 192,896 | |
Stockholders’ equity (deficit): | ||
Preferred stock, $0.001 par value; 10,000,000 shares and no shares authorized as of December 31, 2018 and 2017, respectively; no shares issued and outstanding as of December 31, 2018 and 2017 | ||
Common stock, $0.001 par value; 200,000,000 shares and 236,092,611 shares authorized as of December 31, 2018 and 2017, respectively; 45,139,955 shares and 9,582,791 shares issued and outstanding as of December 31, 2018 and 2017, respectively | 45 | 10 |
Additional paid-in capital | 371,257 | 55,204 |
Accumulated deficit | (246,203) | (148,808) |
Accumulated other comprehensive income | 196 | 79 |
Total stockholders’ equity (deficit) | 125,295 | (93,515) |
Total liabilities, redeemable convertible preferred stock and stockholders’ equity (deficit) | $ 287,651 | $ 198,547 |
Condensed Consolidated Balanc_2
Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares | Dec. 31, 2018 | Dec. 31, 2017 |
Redeemable convertible preferred stock, shares authorized | 0 | 145,833,064 |
Redeemable convertible preferred stock, shares Issued | 0 | 142,288,292 |
Redeemable convertible preferred stock, shares outstanding | 0 | 142,288,292 |
Preferred stock, par value | $ 0.001 | $ 0.001 |
Preferred stock, shares authorized | 10,000,000 | 0 |
Preferred stock, shares Issued | 0 | 0 |
Preferred stock, shares outstanding | 0 | 0 |
Common stock, par value | $ 0.001 | $ 0.001 |
Common stock, shares authorized | 200,000,000 | 236,092,611 |
Common stock, shares issued | 45,139,955 | 9,582,791 |
Common stock, shares outstanding | 45,139,955 | 9,582,791 |
Series A Series B And Series C Redeemable Convertible Preferred Stock [Member] | ||
Redeemable convertible preferred stock, par value | $ 0.001 | $ 0.001 |
Redeemable convertible preferred stock, shares authorized | 0 | 145,833,064 |
Redeemable convertible preferred stock, shares Issued | 0 | 142,288,292 |
Redeemable convertible preferred stock, shares outstanding | 0 | 142,288,292 |
Consolidated Statements of Oper
Consolidated Statements of Operations - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Income Statement [Abstract] | ||
Collaboration revenue | $ 1,420 | |
Operating expenses: | ||
Research and development | 58,024 | $ 47,023 |
General and administrative | 22,606 | 14,311 |
Change in fair value of contingent consideration | 25,020 | 17,914 |
Total operating expenses | 105,650 | 79,248 |
Loss from operations | (104,230) | (79,248) |
Other income (expense): | ||
Interest income | 1,323 | 281 |
Other income (expense), net | (53) | 43 |
Total other income (expense), net | 1,270 | 324 |
Loss before benefit from income taxes | (102,960) | (78,924) |
Benefit from income taxes | 5,565 | 12,481 |
Net loss | (97,395) | (66,443) |
Accretion of redeemable convertible preferred stock to redemption value | (644) | (719) |
Net loss attributable to common stockholders | $ (98,039) | $ (67,162) |
Net loss per share attributable to common stockholders—basic and diluted | $ (3.64) | $ (8.66) |
Weighted average common shares outstanding—basic and diluted | 26,945,508 | 7,756,180 |
Consolidated Statements of Comp
Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Statement Of Income And Comprehensive Income [Abstract] | ||
Net loss | $ (97,395) | $ (66,443) |
Other comprehensive income: | ||
Unrealized gains on available-for-sale securities, net of tax of $0 | 117 | 79 |
Comprehensive loss | $ (97,278) | $ (66,364) |
Consolidated Statements of Co_2
Consolidated Statements of Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Statement Of Income And Comprehensive Income [Abstract] | ||
Unrealized gains on available-for-sale securities, tax | $ 0 | $ 0 |
Consolidated Statements of Rede
Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands | Total | Shire's MRT Program [Member] | Common Stock [Member] | Common Stock [Member]Shire's MRT Program [Member] | Additional Paid-in Capital [Member] | Additional Paid-in Capital [Member]Shire's MRT Program [Member] | Accumulated Deficit [Member] | Accumulated Other Comprehensive Income [Member] | Redeemable Convertible Preferred Stock [Member] |
Beginning balances at Dec. 31, 2016 | $ (38,590) | $ 9 | $ 43,766 | $ (82,365) | |||||
Redeemable convertible preferred stock, shares outstanding, beginning balance at Dec. 31, 2016 | 121,085,582 | ||||||||
Redeemable Convertible Preferred Stock, beginning balance at Dec. 31, 2016 | $ 150,277 | ||||||||
Beginning balance, Shares at Dec. 31, 2016 | 8,532,723 | ||||||||
Forfeited restricted common stock, Shares | (100,563) | ||||||||
Issuance of Series C redeemable convertible preferred stock net issuance costs, Shares | 21,202,710 | ||||||||
Issuance of Series C redeemable convertible preferred stock, net of issuance costs | $ 41,900 | ||||||||
Issuance of common stock in full/partial settlement of contingent consideration anti-dilution liability | 7,978 | $ 1 | 7,977 | ||||||
Issuance of common stock in full/ partial settlement of contingent consideration anti-dilution liability, Shares | 1,079,765 | ||||||||
Issuance of common stock in connection with acquisition of MRT Program | $ 500 | $ 500 | |||||||
Issuance of common stock in connection with acquisition of MRT program, Shares | 70,866 | 70,866 | |||||||
Unrealized gains on available-for-sale securities | 79 | $ 79 | |||||||
Stock-based compensation expense | 3,680 | 3,680 | |||||||
Accretion of redeemable convertible preferred stock to redemption value | (719) | (719) | $ 719 | ||||||
Net loss | (66,443) | (66,443) | |||||||
Ending balances at Dec. 31, 2017 | $ (93,515) | $ 10 | 55,204 | (148,808) | 79 | ||||
Redeemable convertible preferred stock, shares outstanding, ending balance at Dec. 31, 2017 | 142,288,292 | 142,288,292 | |||||||
Redeemable Convertible Preferred Stock, ending balance at Dec. 31, 2017 | $ 192,896 | $ 192,896 | |||||||
Ending balance, Shares at Dec. 31, 2017 | 9,582,791 | ||||||||
Forfeited restricted common stock | 2 | 2 | |||||||
Forfeited restricted common stock, Shares | (2,446) | ||||||||
Conversion of redeemable convertible preferred stock to common stock | 193,540 | $ 26 | 193,514 | ||||||
Conversion of redeemable convertible preferred stock to common stock,Shares | (142,288,292) | ||||||||
Conversion of redeemable convertible preferred stock to common stock | $ (193,540) | ||||||||
Conversion of redeemable convertible preferred stock to common stock, Shares | 25,612,109 | ||||||||
Issuance of common stock in connection with IPO, net of commisions and offering costs | 113,192 | $ 9 | 113,183 | ||||||
Issuance of common stock in connection with IPO, net of commisions and offering costs, Shares | 9,714,371 | ||||||||
Issuance of common stock in full/partial settlement of contingent consideration anti-dilution liability | 2,387 | 2,387 | |||||||
Issuance of common stock in full/ partial settlement of contingent consideration anti-dilution liability, Shares | 183,619 | ||||||||
Issuance of common stock due to the aggregation of fractional shares in connection with the reverse stock split | 52 | ||||||||
Exercise of stock options | 278 | 278 | |||||||
Exercise of stock options, Shares | 49,459 | ||||||||
Unrealized gains on available-for-sale securities | 117 | 117 | |||||||
Stock-based compensation expense | 7,333 | 7,333 | |||||||
Accretion of redeemable convertible preferred stock to redemption value | (644) | (644) | $ 644 | ||||||
Net loss | (97,395) | (97,395) | |||||||
Ending balances at Dec. 31, 2018 | $ 125,295 | $ 45 | $ 371,257 | $ (246,203) | $ 196 | ||||
Redeemable convertible preferred stock, shares outstanding, ending balance at Dec. 31, 2018 | 0 | ||||||||
Ending balance, Shares at Dec. 31, 2018 | 45,139,955 |
Consolidated Statements of Re_2
Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Thousands | 12 Months Ended |
Dec. 31, 2017USD ($) | |
Series C Preferred Stock | |
Issuance of redeemable convertible preferred stock, issuance costs | $ 81 |
Consolidated Statements of Cash
Consolidated Statements of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Cash flows from operating activities: | ||
Net loss | $ (97,395) | $ (66,443) |
Adjustments to reconcile net loss to net cash used in operating activities: | ||
Depreciation and amortization expense | 2,841 | 1,585 |
Stock-based compensation expense | 7,333 | 3,680 |
Change in fair value of contingent consideration | 25,020 | 17,914 |
Deferred income tax benefit | (5,565) | (12,481) |
Accretion of discount on short-term investments | (72) | |
Changes in operating assets and liabilities, net of effects of acquisition: | ||
Prepaid expenses and other assets | (1,346) | (2,262) |
Accounts payable | 658 | 4,025 |
Accrued expenses | 2,271 | 2,312 |
Deferred rent | 470 | 954 |
Deferred revenue | 43,580 | |
Net cash used in operating activities | (22,133) | (50,788) |
Cash flows from investing activities: | ||
Purchases of investments | (136,694) | (70,767) |
Sales and maturities of investments | 57,984 | 73,840 |
Purchases of property and equipment | (6,580) | (2,769) |
Net cash provided by (used in) investing activities | (85,290) | 304 |
Cash flows from financing activities: | ||
Proceeds from issuance of Series C redeemable convertible preferred stock, net of issuance costs | 41,900 | |
Proceeds from initial public offering of common stock, net of underwriting discounts and commissions | 117,447 | |
Payments of initial public offering costs | (4,102) | (153) |
Proceeds from option exercises | 278 | |
Net cash provided by financing activities | 113,623 | 41,747 |
Net increase (decrease) in cash, cash equivalents and restricted cash | 6,200 | (8,737) |
Cash, cash equivalents and restricted cash at beginning of period | 50,024 | 58,761 |
Cash, cash equivalents and restricted cash at end of period | 56,224 | 50,024 |
Cash, cash equivalents and restricted cash at end of period: | ||
Cash and cash equivalents | 55,199 | 48,058 |
Restricted cash | 1,025 | 1,966 |
Cash, cash equivalents and restricted cash at end of period | 56,224 | 50,024 |
Supplemental disclosure of non-cash investing and financing activities: | ||
Purchases of property and equipment included in accounts payable and accrued expenses | 49 | 687 |
Deferred offering costs included in accounts payable and accrued expenses | 358 | |
Accretion of redeemable convertible preferred stock to redemption value | 644 | 719 |
Shire's MRT Program [Member] | Settlement of Contingent Consideration Anti-dilution Liability [Member] | ||
Supplemental disclosure of non-cash investing and financing activities: | ||
Issuance of common stock in settlement of contingent consideration anti-dilution liability | $ 2,387 | 7,978 |
Shire's MRT Program [Member] | Transaction Costs [Member] | ||
Supplemental disclosure of non-cash investing and financing activities: | ||
Issuance of common stock in connection with Business Combination | $ 500 |
Nature of the Business and Basi
Nature of the Business and Basis of Presentation | 12 Months Ended |
Dec. 31, 2018 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Nature of the Business and Basis of Presentation | 1. Nature of the Business and Basis of Presentation Translate Bio, Inc. (the “Company”) is a clinical-stage messenger RNA (“mRNA”) therapeutics company developing a new class of potentially transformative medicines to treat diseases caused by protein or gene dysfunction. Using its proprietary mRNA therapeutic platform (“MRT platform”), the Company creates mRNA that encodes functional proteins. The Company’s mRNA is delivered to the target cell where the cell’s own machinery recognizes it and translates it, restoring or augmenting protein function to treat or prevent disease. The Company is initially focused on restoring the expression of intracellular and transmembrane proteins, areas that have eluded conventional protein therapeutics, in patients with genetic diseases where there is high unmet medical need. The Company is developing its lead MRT product candidate for the lung, MRT5005, for the treatment of cystic fibrosis (“CF”). The Company is conducting a Phase 1/2 clinical trial to evaluate the safety and efficacy of MRT5005 and anticipates reporting interim data from this trial in the second half of 2019. The Company is developing its lead MRT product candidate for the liver, MRT5201, for the treatment of ornithine transcarbamylase (“OTC”) deficiency. In December 2018, the Company submitted an investigational new drug application (“IND”) for MRT5201, which the U.S. Food and Drug Administration (the “FDA”) has placed on clinical hold. The FDA is requiring additional preclinical toxicology data. The Company has identified the additional preclinical studies required, and plans to complete these studies and submit a response to the FDA in the fourth quarter of 2019. In December 2016, the Company acquired from Shire Human Genetic Therapies, Inc. (“Shire”), a subsidiary of Shire plc, rights to the assets of Shire’s mRNA therapy platform (the “MRT Program”), including the cystic fibrosis transmembrane conductance regulator (“CFTR”) and OTC deficiency mRNA therapy programs. In connection with this acquisition, Shire received shares of the Company’s common stock, with related anti-dilution rights, and is eligible for future milestone and earnout payments on products developed with the MRT technology (see Note 4). The Company is subject to risks common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries, Translate Bio MA, Inc. and Translate Bio Securities Corporation, from their date of incorporation. All intercompany accounts and transactions have been eliminated in consolidation. Reverse Stock Split On June 15, 2018, the Company effected a one-for-5.5555 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s redeemable convertible preferred stock (see Note 8). Accordingly, all share and per share amounts for all periods presented in the accompanying consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and the associated adjustment of the preferred stock conversion ratios. Initial Public Offering On June 27, 2018, the Company’s registration statement on Form S-1 relating to its initial public offering of its common stock (“the IPO”) was declared effective by the Securities and Exchange Commission (“SEC”). In the IPO, which closed on July 2, 2018, the Company issued and sold 9,350,000 shares of common stock at a public offering price of $13.00 per share. On July 24, 2018, the Company issued and sold an additional 364,371 shares of common stock at a price of $13.00 per share pursuant to the exercise of the underwriters’ over-allotment option in the IPO. The aggregate net proceeds to the Company from the IPO, inclusive of the proceeds from the over-allotment exercise, were $113.2 million after deducting underwriting discounts and commissions of $8.8 million and offering expenses of $4.3 million. Upon closing of the IPO, all 142,288,292 shares of the Company’s redeemable convertible preferred stock then outstanding converted into an aggregate of 25,612,109 shares of common stock. Sanofi Pasteur Collaboration and Licensing Agreement On June 8, 2018, the Company entered into a collaboration and license agreement with Sanofi Pasteur Inc. (“Sanofi”), the vaccines global business unit of Sanofi S.A., to develop mRNA vaccines for up to five infectious disease pathogens (the “Sanofi Agreement”). The Sanofi Agreement became effective on July 9, 2018. Under the Sanofi Agreement, the Company and Sanofi will jointly conduct research and development activities to advance mRNA vaccines and mRNA vaccine platform development during a three-year research term, which may be extended by mutual agreement. Following the research term, the Company is obligated to manufacture clinical product for Sanofi, which the Company estimates may take up to eight years to complete. The Company is eligible to receive up to $805.0 million in payments, which includes an upfront payment of $45.0 million, which the Company received in July 2018; certain development, regulatory and sales-related milestones across several vaccine targets; and option exercise fees if Sanofi exercises its option related to development of vaccines for additional pathogens. The Company is also eligible to receive tiered royalty payments associated with worldwide sales of the developed vaccines, if any (see Note 3). Going Concern In accordance with Accounting Standards Update (“ASU”) No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40) The Company’s financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business. Through December 31, 2018, the Company has funded its operations with proceeds from the sale of redeemable convertible preferred stock and the sale of bridge units, which ultimately converted into shares of preferred stock, the proceeds from the IPO and an upfront payment received under the Sanofi Agreement. The Company has incurred recurring losses and cash outflows from operations since its inception, including net losses of $97.4 million and $66.4 million for the years ended December 31, 2018 and 2017, respectively. In addition, the Company had an accumulated deficit of $246.2 million as of December 31, 2018. The Company expects to continue to generate operating losses for the foreseeable future. As of March 21, 2019, the date of issuance of these consolidated financial statements, the Company expects that its cash, cash equivalents and short-term investments of $144.1 million as of December 31, 2018 will be sufficient to fund its operating expenses and capital expenditure requirements into the second quarter of 2020. The Company expects to seek additional funding through equity financings, debt financings, or other capital sources, including collaborations with other companies or other strategic transactions. If the Company is unable to obtain funding, the Company will be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects, or the Company may be unable to continue operations. Based on its recurring losses and cash outflows from operations since inception, expectation of continuing operating losses and cash outflows from operations for the foreseeable future and the need to raise additional capital to finance its future operations, the Company concluded that there was substantial doubt about its ability to continue as a going concern. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual for research and development expenses, the revenue recognized from collaboration agreements, the valuation of common stock and stock-based awards, the valuation of assets acquired and liabilities assumed in business combinations, and the impairment of identifiable intangible assets and goodwill. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. Cash and Cash Equivalents All highly liquid investments purchased with an original maturity date of three months or less at the date of purchase are considered to be cash equivalents. Cash equivalents consisted of money market funds as of December 31, 2018 and 2017. Investments The Company’s debt security investments are classified as available-for-sale and are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity (deficit). Realized gains and losses and declines in value determined to be other than temporary are based on the specific identification method and are included as a component of other income (expense), net in the consolidated statements of operations. The Company evaluates its investments with unrealized losses for other-than-temporary impairment. When assessing investments for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary,” the Company reduces the investment to fair value through a charge to the statement of operations. No such adjustments were necessary during the periods presented. The Company’s investments as of December 31, 2018 and 2017 had original maturities of less than one year. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents as well as short-term investments. Cash, cash equivalents and short-term investments consist of demand deposits, money market funds and U.S. government agency bonds. The Company generally maintains balances in various operating accounts with financial institutions that management believes to be of high credit quality, in amounts that may exceed federally insured limits. The Company has not experienced any losses related to its cash, cash equivalents and short-term investments and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Restricted Cash In connection with its operating lease commitments, the Company issued letters of credit collateralized by cash deposits that are classified as restricted cash in the consolidated balance sheets. Restricted cash amounts have been classified as current assets based on the release dates of the restrictions under the letters of credit, which occur annually. Deferred Offering Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of proceeds generated as a result of the offering. Should an in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations. As of December 31, 2018, the Company had no deferred offering costs. As of December 31, 2017, the Company recorded deferred offering costs of $0.5 million in connection with its IPO. Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful lives of each asset. Estimated useful lives are periodically assessed to determine if changes are appropriate. Upon retirement or sale, the related cost and accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is included in the consolidated statements of operations. Repair and maintenance costs are expensed as incurred. The estimated useful lives of the Company’s property and equipment are as follows: Estimated Useful Life Laboratory equipment 5 years Computer equipment 3 years Office equipment 5 years Leasehold improvements Shorter of lease term or 10 years Costs for capital assets not yet placed into service are capitalized as construction-in-progress and depreciated or amortized in accordance with the above useful lives once placed into service. Property and equipment are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate an asset group for recoverability, the Company compares the forecasted undiscounted cash flows expected to result from the use and eventual disposition of the asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use and eventual disposition of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows using market participant assumptions. The Company did not record any impairment losses on property and equipment during the years ended December 31, 2018 and 2017. Revenue Recognition The terms of the Company’s collaboration agreements may include consideration such as non-refundable license fees, funding of research and development services, payments due upon the achievement of clinical and pre-clinical performance-based development milestones, regulatory milestones, manufacturing services, sales-based milestones and royalties on product sales. The Company had no revenue prior to the Sanofi Agreement, therefore the adoption of Financial Accounting Standards Board (“FASB”) ASC 606, Revenue from Contracts with Customers The Company recognizes the transaction price allocated to upfront license payments as revenue upon delivery of the license to the customer and resulting ability of the customer to use and benefit from the license, if the license is determined to be distinct from the other performance obligations identified in the contract. If the license is considered to not be distinct from other performance obligations, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied (i) at a point in time, but only for licenses determined to be distinct from other performance obligations in the contract, or (ii) over time, and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from license payments. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Sanofi Agreement entitles the Company to additional payments upon the achievement of performance-based milestones. These milestones are generally categorized into three types: development milestones, generally based on the advancement of the Company’s pipeline and initiation of clinical trials; regulatory milestones, generally based on the submission, filing or approval of regulatory applications such as a new drug application (“NDA”) in the United States; and sales-based milestones, generally based on meeting specific thresholds of sales in certain geographic areas. The Company is also eligible to receive from Sanofi tiered royalty payments on worldwide net sales of mRNA vaccines. For each collaboration that includes development milestone payments, the Company evaluates whether it is probable that the consideration associated with each milestone will not be subject to a significant reversal in the cumulative amount of revenue recognized. Amounts that meet this threshold are included in the transaction price using the most likely amount method, whereas amounts that do not meet this threshold are considered constrained and excluded from the transaction price until they meet this threshold. Milestones tied to regulatory approval, and therefore not within the Company’s control, are considered constrained until such approval is received. Upfront and ongoing development milestones per its collaboration agreements are not subject to refund if the development activities are not successful. At the end of each subsequent reporting period, the Company re-evaluates the probability of a significant reversal of the cumulative revenue recognized for the milestones, and, if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues from collaborators in the period of adjustment. The Company agreement that includes . The Company considers the underlying facts and circumstances of these agreements, noting whether the future payments are contingent upon future sales and whether they are dependent on a third party’s ability to successfully commercialize a product using the licensed intellectual property. The Company also considers whether the license is the only, or predominant, item to which the milestone payments and royalties relate. If the Company concludes the license is the predominant item in the agreement, therefore the primary driver of value, the ASC 606 requires the Company to allocate the arrangement consideration on a relative standalone selling price basis for each performance obligation after determining the transaction price of the contract and identifying the performance obligations to which that amount should be allocated. The relative standalone selling price is defined in ASC 606 as the price at which an entity would sell a promised good or service separately to a customer. If other observable transactions in which the Company has sold the same performance obligation separately are not available, the Company is required to estimate the standalone selling price of each performance obligation. Key assumptions to determine the standalone selling price may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. Whenever the Company determines that a contract should be accounted for as a combined performance obligation it will utilize the cost-to-cost input method. Revenue will be recognized over time using the cost-to-cost input method, based on the total estimated costs to fulfill the obligations. The Company will recognize revenue as services are delivered. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. The Company evaluates its collaborative agreements for proper classification in the consolidated statements of operations based on the nature of the underlying activity. Transactions between collaborators recorded in the Company’s consolidated statements of operations are recorded on either a gross or net basis, depending on the characteristics of the collaborative relationship. For revenue generating arrangements where the Company, as a vendor, provides consideration to a licensor or collaborator, as a customer, the Company applies the accounting standard that governs such transactions. This standard addresses the accounting for revenue arrangements where both the vendor and the customer make cash payments to each other for services and/or products. A payment to a customer is presumed to be a reduction of the transaction price unless the Company receives an identifiable benefit for the payment and it can reasonably estimate the fair value of the benefit received. Payments to a customer that are deemed a reduction of the transaction price are recorded first as a reduction of revenue, to the extent of both cumulative revenue recorded to date and probable future revenues, which include any unamortized deferred revenue balances, under all arrangements with such customer, and then as an expense. Payments that are not deemed to be a reduction of the transaction price are recorded as an expense. Consideration that does not meet the requirements to satisfy the above revenue recognition criteria is a contract liability and is recorded as deferred revenue in the consolidated balance sheets. Although the Company follows detailed guidelines in measuring revenue, certain judgments affect the application of its revenue policy. For example, in connection with the Sanofi Agreement, the Company has recorded short-term and long-term deferred revenue on its consolidated balance sheets based on the Company’s best estimate of when such revenue will be recognized. Short-term deferred revenue consists of amounts that are expected to be recognized as revenue in the next 12 months. Amounts that the Company expects will not be recognized within the next 12 months are classified as long-term deferred revenue. The estimate of deferred revenue also reflects management’s estimate of the periods of the Company’s involvement in certain of its collaborations. The Company’s performance obligations under these collaborations consist of participation on steering committees and the performance of other research and development services. In certain instances, the timing of satisfying these obligations can be difficult to estimate. Accordingly, the Company’s estimates may change in the future. Such changes to estimates would result in a change in revenue recognition amounts. If these estimates and judgments change over the course of these agreements, it may affect the timing and amount of revenue that the Company will recognize and record in future periods. At December 31, 2018, the Company had short-term and long-term deferred revenue of $2.6 million and $41.8 million, respectively, related to the Sanofi Agreement. Under ASC 606, the Company will recognize revenue and record a receivable when it fulfills its performance obligations under the Sanofi Agreement. When no further performance obligation is required to be satisfied, the Company will recognize revenue for the portion satisfied and record a receivable. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. The Company expenses incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that the Company would have recognized is one year or less or the amount is immaterial. At December 31, 2018, the Company has not capitalized any costs to obtain any of its contracts. Business Combinations The Company accounts for business combinations using the acquisition method of accounting. Application of this method of accounting requires that (i) identifiable assets acquired (including identifiable intangible assets) and liabilities assumed generally be measured and recognized at fair value as of the acquisition date and (ii) the excess of the purchase price over the net fair value of identifiable assets acquired and liabilities assumed be recognized as goodwill, which is not amortized for accounting purposes but is subject to testing for impairment at least annually. Acquired in-process research and development (“IPR&D”) is recognized at fair value and initially characterized as an indefinite-lived intangible asset, irrespective of whether the acquired IPR&D has an alternative future use. Transaction costs related to business combinations are expensed as incurred. Determining the fair value of assets acquired and liabilities assumed in a business combination requires management to use significant judgment and estimates, especially with respect to intangible assets. Critical estimates in valuing certain identifiable assets include, but are not limited to, the selection of valuation methodologies, estimates of future revenue and cash flows, expected long-term market growth, future expected operating expenses, costs of capital and appropriate discount rates. Management’s estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and, as a result, actual results may differ materially from estimates. During the measurement period, which extends no later than one year from the acquisition date, the Company may record certain adjustments to the carrying value of the assets acquired and liabilities assumed with the corresponding offset to goodwill. After the measurement period, all adjustments are recorded in the consolidated statements of operations as operating expenses or income. Acquisition-related contingent consideration, which consists of potential milestone and earnout payment obligations as well as anti-dilution rights provided to Shire (see Note 3), was recorded in the consolidated balance sheets at its acquisition-date estimated fair value, in accordance with the acquisition method of accounting. The fair value of the acquisition-related contingent consideration is remeasured each reporting period, with changes in fair value recorded in the consolidated statements of operations. The fair value measurement is based on significant inputs not observable by market participants and thus represents a Level 3 input in the fair value hierarchy (see Note 4). Asset Acquisitions The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire IPR&D with no alternative future use is charged to expense at the acquisition date. In-Process Research and Development The fair value of IPR&D acquired through a business combination is capitalized as an indefinite- and definite-lived intangible asset until the completion or abandonment of the related research and development activities. When the related research and development is completed or a change in circumstance occurs that defines the useful life, the asset is reclassified to a definite-lived asset and amortized over its estimated useful life. When a change between these classes occurs, the Company will perform an impairment test. The fair value of an IPR&D intangible asset is typically determined using an income approach whereby management forecasts the net cash flows expected to be generated by the asset over its estimated useful life. The net cash flows reflect the asset’s stage of completion, the probability of technical success, the projected costs to complete, expected market competition, and an assessment of the asset’s life-cycle. The net cash flows are then adjusted to present value by applying an appropriate discount rate that reflects the risk factors associated with the cash flow streams. Indefinite-lived IPR&D is not subject to amortization, but is tested annually for impairment or more frequently if there are indicators of impairment. The Company tests its indefinite-lived IPR&D annually for impairment on October 1st. In testing indefinite-lived IPR&D for impairment, the Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances would indicate that it is more likely than not that its fair value is less than its carrying amount, or the Company can perform a quantitative impairment analysis to determine the fair value of the indefinite-lived IPR&D without performing a qualitative assessment. Qualitative factors that the Company considers include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If the Company chooses to first assess qualitative factors and the Company determines that it is more likely than not that the fair value of the indefinite-lived IPR&D is less than its carrying amount, the Company would then determine the fair value of the indefinite-lived IPR&D. Under either approach, if the fair value of the indefinite-lived IPR&D is less than its carrying amount, an impairment charge is recognized in the consolidated statements of operations. During the years ended December 31, 2018 and 2017, the Company did not recognize any impairment charges related to its definite-lived IPR&D (see Note 4). In December 2018, the Company submitted an IND to the FDA to support the initiation of a Phase 1/2 clinical trial for MRT5201 in patients with OTC deficiency. In January 2019, the FDA notified the Company that its IND for MRT5201 was placed on clinical hold. The Company determined this clinical hold was an indicator of impairment and as a result, retested the indefinite-lived IPR&D related to the OTC program for impairment. The Company performed a quantitative impairment analysis whereby the Company forecasted the net cash flows expected to be generated by the indefinite-lived IPR&D related to the OTC program over its estimated useful life. The net cash flows reflected the program’s stage of completion, the probability of technical success, the projected costs to complete, expected market competition and an assessment of the program’s life-cycle. The net cash flows were then adjusted to present value by applying an appropriate discount rate that reflects the risk factors associated with the cash flow streams. Following this retest the Company determined the indefinite-lived IPR&D related to the OTC program was not impaired. Therefore, the Company did not recognize an impairment charge. Definite-lived IPR&D is recorded at fair value and amortized over the greater of economic consumption or on a straight-line basis over its estimated useful life. Definite-lived IPR&D is tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. If an impairment review is performed to evaluate an asset group for recoverability, the Company compares the forecasted undiscounted cash flows expected to result from the use and eventual disposition of the asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use and eventual disposition of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows using market participant assumptions. Goodwill Goodwill represents the excess of the fair value of the consideration transferred over the fair value of the net tangible and identifiable intangible assets acquired in a business combination. Goodwill is not subject to amortization, but is tested annually for impairment or more frequently if there are indicators of impairment. The Company tests its goodwill annually for impairment on October 1st. The Company has determined that there is a single reporting unit for purposes of testing goodwill for impairment. In testing goodwill for impairment, the Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances would indicate that it is more likely than not that the fair value of the reporting unit was less than its carrying amount, or the Company can perform a two-step quantitative impairment analysis without performing a qualitative assessment. Examples of such events or circumstances considered in the Company’s qualitative assessment include, but are not limited to, a significant adverse change in legal or business climate, an adverse regulatory action or unanticipated competition. If the Company chooses to first assess qualitative factors and the Company determines that it is more likely than not that the fair value of its reporting unit is less than its carrying amount, the Company would then perform a two-step quantitative impairment test. The two-step test starts with comparing the fair value of the reporting unit to the carrying amount of a reporting unit, including goodwill. If the fair value of the reporting unit exceeds the carrying amount, no impairment loss is recognized. However, if the fair value of the reporting unit is less than its carrying value, the second step of the impairment test is performed to determine if goodwill is impaired. If the Company determines that goodwill is impaired, the carrying value of the goodwill is written down to its fair value and an impairment charge is recognized in the consolidated statements of operations. During the years ended December 31, 2018 and 2017, the Company did not recognize any impairment charges related to goodwill. Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and short-term investments are carried at fair value, determined based on Level 2 inputs in the fair value hierarchy described above (see Note 5). The Company’s contingent consideration liability is carried at fair value, determined based on Level 3 inputs in the fair value hierarchy described above (see Note 5). The carrying values of the Company’s prepaid expenses and other current assets, accounts payable, accrued expenses and other short-term liabilities approximate their fair values due to the short-term nature of these assets and liabilities. Segment Information The Company manages its operations as a single operating segment for the purposes of assessing performance and making operating decisions. The Company’s primary focus is on the advancement of the Company’s MRT platform to treat diseases caused by protein or gene dysfunction. Research and Development Costs Costs associated with internal research and development and external research and development services, including drug development and preclinical studies, are expensed as incurred. Research and development expenses include costs for salaries, employee benefits, subcontractors, facility-related expenses, depreciation and amortization, including amortization related to definite-lived IPR&D intangible assets, stock-based compensation, third-party license fees, laboratory supplies, and external costs of outside vendors engaged to conduct discovery, preclinical and clinical development activities and clinical trials as well as to manufacture clinical trial materials, and other costs. The Company recognizes external research and development costs based on an evaluation of the progress to completion of specific tasks using information provided to the Company by its service providers. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. Such prepaid expenses are recognized as an expense when the services have been performed or the goods have been delivered, or when it is no longer expected that the goods will be delivered or the services rendered. Upfront payments, milestone payments (other than those deemed contingent consideration in a business combination) and annual maintenance fees under license agreements are expensed in the period in which they are incurred. Research and Development Contract Costs and Accruals The Company has entered into various research and development-related contracts with companies both inside and outside of the United States. The related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ materially from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs. Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses. Stock-Based Compensation The Company measures all stock-based awards granted to employees and directors based on their fair value on the date of the grant and recognizes compensation expense for those awards over the requisite service period, which is generally the vesting period of the respective award. For stock-based awards with service-based vesting conditions, the Company recognizes compensation expense using the straight-line method. For stock-based awards with both performance-based and service-based vesting conditions, the Company recognizes compensation expense using the graded-vesting method over the requisite service period, commencing when achievement of the performance condition becomes probable. The Company recognizes adjustments to compensation expense for forfeitures as they occur. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model, which requires i |
Collaboration Agreement
Collaboration Agreement | 12 Months Ended |
Dec. 31, 2018 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Collaboration Agreement | 3. Sanofi Collaboration and License Agreement On June 8, 2018, the Company entered into the Sanofi Agreement, a collaboration and license agreement with Sanofi to develop mRNA vaccines and mRNA vaccine platform development for up to five infectious disease pathogens (the “Licensed Fields”). The Sanofi Agreement became effective on July 9, 2018. Under the Sanofi Agreement, the Company and Sanofi have agreed to collaborate to perform certain research and development activities to advance mRNA vaccines and mRNA vaccine platform development during a three-year research term, which may be extended by mutual agreement. Following the research term, the Company is obligated to manufacture clinical product for Sanofi, which the Company estimates may take up to eight years to complete. The collaboration activities will be subject to a collaboration plan to be updated annually. The Sanofi Agreement provides for Sanofi to make an upfront payment to the Company of $45.0 million, which the Company received in July 2018, as well as certain potential milestone payments and option payments, each as further described below. In addition, the Company is eligible to receive from Sanofi tiered royalty payments on worldwide net sales of mRNA vaccines. Under the Sanofi Agreement, the Company and Sanofi created a governance structure, including committees and working groups, to manage the activities under the collaboration. If the Company and Sanofi do not mutually agree on certain decisions, Sanofi would be able to break a deadlock without the Company’s consent. The collaboration includes an estimated budget. Sanofi is responsible for paying the Company’s employee costs, out-of-pocket costs paid to third parties and manufacturing costs, up to a specified amount. Under the terms of the Sanofi Agreement, the Company has granted to Sanofi exclusive, worldwide licenses under applicable patents, patent applications, know-how and materials, including those arising under the collaboration, to develop, commercialize and manufacture mRNA vaccines to prevent, treat or cure diseases, disorders or conditions in humans caused by any of three of the Licensed Fields. In addition, pursuant to the terms of the Sanofi Agreement and subject to certain limitations, Sanofi has options to add up to two additional infectious disease pathogens within the granted licenses to the Licensed Fields by exercising either option or both options during a specified option term and paying the Company a $5.0 million fee per added pathogen. If, prior to the exercise of the options by Sanofi, the Company receives a bona fide third-party offer to acquire rights to the field to which an option relates, the Company must notify Sanofi of such offer, and if Sanofi does not exercise its option as to the applicable field, such field will no longer be subject to the option. The Company and Sanofi retain the rights to perform their respective obligations and exercise their respective rights under the Sanofi Agreement, and Sanofi may grant sublicenses to affiliates or third parties. Sanofi has also granted the Company non-exclusive, sublicensable licenses under patent rights claiming certain improvements that Sanofi may make to the technology the Company has licensed to it or claiming certain technology arising from the collaboration and owned by Sanofi. The Company may exercise such licenses to develop, manufacture and commercialize products, other than products that use a vaccine to prevent, treat or cure a disease, disorder or condition in humans caused by an infectious disease pathogen. If the Company commercializes any product covered by such a Sanofi patent right, the Company would pay Sanofi a royalty of a low single-digit percentage. Sanofi may terminate these licenses to the Company if the Company materially breaches the terms of the license and the breach remains uncured for a specified period, which may be extended in certain circumstances. Sanofi has sole responsibility for all commercialization activities for mRNA vaccines in the Licensed Fields and is obligated to bear all costs in connection with any such commercialization. The Company and Sanofi intend to enter into a supply agreement pursuant to which the Company would be responsible for manufacturing certain non-clinical and clinical mRNA vaccines and materials containing mRNA until the Company transfers such manufacturing capabilities to Sanofi. The Company would be entitled to receive payments for manufacturing mRNA vaccines under the supply agreement. The Sanofi Agreement provides that the Company is eligible to receive aggregate potential payments of up to $805.0 million from Sanofi, which includes an upfront payment, potential milestone payments and potential option exercise payments. In July 2018, Sanofi paid the Company a $45.0 million upfront payment in respect of the licenses and options granted to Sanofi. Sanofi will also pay the Company $5.0 million with respect to each additional Licensed Field for which it exercises an option. Sanofi has also agreed to pay the Company milestone payments upon the achievement of specified development, regulatory and commercialization milestones. In particular, the Company is entitled to receive development and regulatory milestone payments of up to $63.0 million per Licensed Field and sales milestone payments of up to $85.0 million per Licensed Field. In addition, the Company is entitled to receive a $10.0 million milestone payment from Sanofi following completion of the technology and process transfer. Sanofi has agreed to pay the Company a tiered royalty on worldwide net sales of all mRNA vaccines within each Licensed Field ranging from a high single-digit percentage to a low teens percentage, depending on quarterly net sales by Sanofi, its affiliates and its sublicensees. The royalty paid to the Company can be reduced with respect to a product once the relevant licensed patent rights expire or if additional licensed technology is required, but the royalty payments generally may not fall below the Company’s royalty obligations to third parties plus a royalty of a low single-digit percentage. Royalty payments under the Sanofi Agreement are payable on a product-by-product and country-by-country basis beginning on the launch of the product in the country until the later of the expiration of the last valid claim covering such product or 10 years after the launch of such product in such country. The Sanofi Agreement provides that it will remain in effect until terminated in accordance with its terms. Either the Company or Sanofi may terminate the Sanofi Agreement in its entirety if the other party is subject to certain insolvency proceedings. Either party may terminate the Sanofi Agreement in its entirety or with respect to a particular Licensed Field, country or product if the other party materially breaches the Sanofi Agreement and the breach remains uncured for a specified period, which may be extended in certain circumstances. Sanofi may also terminate the Sanofi Agreement in its entirety or with respect to a particular Licensed Field, country or product for safety reasons or for convenience, in each case after a specified notice period. After termination of the Sanofi Agreement, Sanofi may continue to manufacture and commercialize the terminated products for a specified period of time, subject to Sanofi’s payment obligations. Accounting Under ASC 606 In determining the appropriate amount of revenue to be recognized under ASC 606, the Company performed the following steps: (i) identified the promised goods or services in the contract; (ii) determined whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company identified the following promised goods or services contained in the Sanofi Agreement: (i) the license it conveyed to Sanofi with respect to the Licensed Fields, (ii) the licensed know-how to be conveyed to Sanofi with respect to the Licensed Fields, (iii) it obligations to perform research and development on the Licensed Fields, (iv) its obligation to transfer licensed materials to Sanofi, (v) its obligation to manufacture and supply certain non-clinical and clinical mRNA vaccines and materials containing mRNA until the Company transfers such manufacturing capabilities to Sanofi and (vi) the technology and process transfer. The Company assessed whether each of these promised goods or services are distinct performance obligations on their own or if they need to be combined with other promises to create a bundle that is a distinct performance obligation. The Company determined that the promised goods and services do not have standalone value and are highly interrelated. Accordingly, the promised goods and services represent one performance obligation. Sanofi’s right to exercise options for up to two additional infectious disease pathogens within the granted licenses to the Licensed Fields are accounted for separately as they do not represent material rights, based on the criteria of ASC 606. Upon the exercise of any option by Sanofi, the contract promises associated with an option target would use a separate proportional performance model for purposes of revenue recognition under ASC 606. The Company determined the transaction price of the Sanofi Agreement to be $161.1 million based upon the probability that the consideration associated with each milestone or reimbursement will not be subject to a significant reversal in the cumulative amount of revenue recognized. The transaction price includes the upfront, non-refundable payment of $45.0 million for the transfer of the combined license, supply and development obligations under the Sanofi Agreement, an estimated $32.6 million in reimbursable employee costs, an estimated $54.5 million in reimbursable development costs including out-of-pocket costs paid to third parties and manufacturing costs, an estimated $19.0 million in milestone payments and an estimated $10.0 million for scaling up the Company’s manufacturing capacity. Reimbursable development costs are payable by Sanofi within 60 days of invoicing. There was no significant financing component or noncash consideration included in the Sanofi Agreement. Under ASC 606, the Company recognized revenue using the cost-to-cost input method, which it believes best depicts the transfer of control to the customer. Under the cost-to-cost input method, the extent of progress towards completion is measured based on the ratio of actual costs incurred to the total estimated costs expected upon satisfying the identified performance obligation. Under this method, revenue is recorded as a percentage of the estimated transaction price based on the extent of progress towards completion. The estimate of the Company’s measure of progress and estimate of variable consideration to be included in the transaction price will be updated at each reporting date as a change in estimate. The amount related to the unsatisfied portion will be recognized as that portion is satisfied over time. The following table summarizes the Company’s net revenues from collaboration (in thousands): Year Ended December 31, 2018 2017 Collaboration revenue $ 1,420 $ — The following table presents the balance of the Company’s contract liabilities (in thousands): December 31, 2018 2017 Contract liabilities Deferred revenues $ 44,413 $ — The Company has accounts receivable of $0.8 million from Sanofi, which is included in prepaids and other current assets on the consolidated balance sheet as of December 31, 2018. The Company considers the total consideration expected to be earned in the next 12 months for services to be performed as short-term deferred revenue, and consideration that is expected to be earned subsequent to 12 months from the balance sheet date as long-term deferred revenue. The Company expects to complete its obligations and recognize all net revenues from the collaboration over eight years. |
Acquisitions, Goodwill and Othe
Acquisitions, Goodwill and Other Intangible Assets | 12 Months Ended |
Dec. 31, 2018 | |
Acquisitions Goodwill And Other Intangible Assets [Abstract] | |
Acquisitions, Goodwill and Other Intangible Assets | 4. Acquisitions, Goodwill and Other Intangible Assets Acquisition of Shire’s MRT Program On December 22, 2016, the Company entered into an asset purchase agreement (as amended on June 7, 2018, the “Shire Agreement”) with Shire pursuant to which Shire sold equipment to and assigned to the Company all of its rights to certain patent rights, permits, real property leases, contracts, regulatory documentation, books and records, and materials related to Shire’s MRT Program, including its CFTR and OTC deficiency mRNA therapeutic programs. The Company assumed no liabilities of Shire as part of the Shire Agreement. As part of the acquisition, the scientific founders of the MRT platform and other key members of the Shire program joined the Company to advance the Company’s MRT platform and the development of its product candidates. Under the Shire Agreement, the Company is obligated to use commercially reasonable efforts to develop and seek and obtain regulatory approval for products that include or are composed of MRT compounds covered by or derived from patent rights or know-how acquired from Shire (“MRT Products”) and to achieve specific developmental milestones. During the earnout period described below, with respect to any MRT Product in any country, the Company is obligated to use commercially reasonable efforts to market and sell such MRT Product in such country. The Company accounted for the acquisition of the assets and employees as a business combination. As consideration for the acquisition, the Company issued 5,815,560 shares of common stock to Shire and agreed to make potential future milestone and earnout payments to Shire upon the occurrence of specified commercial milestones. In particular, the Company is obligated to make milestone payments to Shire of up to $60.0 million in the aggregate upon the occurrence of specified commercial milestones, including upon the first commercial sale of an MRT Product for the treatment of CF and upon the achievement of a specified level of annual net sales with respect to an MRT Product. The Company is also obligated to make additional milestone payments of $10.0 million for each non-CF MRT Product upon the first commercial sale of a non-CF MRT Product; provided that such milestone payments will only be due once for any two non-CF MRT Products that contain the same MRT compounds or once per non-CF MRT Product that is a vaccine developed under the Company’s collaboration with Sanofi (see Note 3). Under the Shire Agreement, the Company is also obligated to pay a quarterly earnout payment of a mid-single-digit percentage of net sales of each MRT Product. The earnout period, which is determined on a product-by-product and country-by-country basis, will begin on the date of the first commercial sale of such MRT Product in such country and will end on the later of (i) 10 years after such first commercial sale and (ii) the expiration of the last valid claim of the patent rights acquired from Shire or derived from patent rights or know-how acquired from Shire covering such MRT Product in such country. Under the Shire Agreement, the Company was obligated to consummate an equity financing of at least $100.0 million (the “Subsequent Financing”). As part of the Shire Agreement, the Company provided Shire anti-dilution rights whereby it agreed to issue Shire additional common stock such that Shire would own, upon the completion of the Subsequent Financing, either (i) 18.0% of the Company’s common stock on an as-converted and fully diluted basis or (ii) if less, 19.9% of the voting power of all then outstanding common stock of the Company, excluding shares of unvested restricted stock. As a result of the Company’s IPO, the Company fully satisfied the Subsequent Financing obligation. In addition, as a result of and concurrent with the closing of the Company’s IPO on July 2, 2018, the Company issued 183,619 shares of common stock to Shire in full satisfaction of the Company’s anti-dilution obligations to Shire (see Note 5). Elements of Purchase Consideration As part of its accounting for the business combination, the Company recorded the fair value of the common stock issued on the acquisition date as well as contingent consideration liabilities for the potential future milestone and earnout payments and for the anti-dilution rights provided to Shire through the completion of the Subsequent Financing. The aggregate acquisition-date fair value of consideration transferred was determined to be $112.2 million, consisting of the following (in thousands): Fair value of common stock $ 41,089 Fair value of contingent consideration — potential milestone and earnout payments 62,666 Fair value of contingent consideration — anti-dilution rights 8,407 Total fair value of purchase consideration $ 112,162 Common Stock Issued at Closing. The fair value of the 5,815,560 shares of common stock issued on the acquisition date, aggregating $41.1 million, was determined based on the fair value of $7.06 per share of common stock estimated by the Company at the acquisition date based, in part, on the results of a third-party valuation. The third-party valuation was prepared using a hybrid method, which used market approaches to estimate the Company’s equity value, including an OPM backsolve based on the $1.98 price per share of Series C redeemable convertible preferred stock sold by the Company in a Series C financing on the same date as the acquisition date of the MRT Program (see Note 8). The hybrid method is a probability-weighted expected return method (“PWERM”) where the equity value in one or more of the scenarios is allocated using an option-pricing method (“OPM”). In the third-party valuation, two types of future-event scenarios were considered: an IPO scenario and a remain-private scenario. Each type of future-event scenario was probability weighted by the Company based on an evaluation of its historical and forecasted performance and operating results, an analysis of market conditions at the time, and its expectations as to the timing and likely prospects of the future-event scenarios. A discount for lack of marketability was then applied to arrive at an indication of fair value per share of the common stock. Liabilities for Contingent Consideration. The fair value of the contingent consideration related to potential future milestone and earnout payments that may be due to Shire was estimated by the Company at the acquisition date based, in part, on the results of a third-party valuation. The third-party valuation was prepared using a discounted cash flow analysis based on various assumptions, including the probability of achieving specified events, discount rates, and the period of time until earnout payments are payable and the conditions triggering the milestone payments are met. The fair value of the contingent consideration related to Shire’s anti-dilution rights was estimated by the Company at the acquisition date based, in part, on the results of a third-party valuation. The third-party valuation was prepared using a PWERM, which considered as inputs the probability of occurrence of events that would trigger the issuance of additional shares, the expected timing of such events, the expected value of the contingently issuable equity upon the occurrence of a triggering event and a risk-adjusted discount rate. The Company assessed the anti-dilution rights provided to Shire and determined that the rights (i) met the definition of a freestanding financial instrument that was not indexed to the Company’s own stock and (ii) did not meet the definition of a derivative. As the rights did not meet the definition of a derivative and did not qualify for equity classification, the Company determined to classify the anti-dilution rights as a liability. Accordingly, the Company recognized the liability at fair value on the acquisition date and recognizes changes in the fair value of the anti-dilution rights at each subsequent reporting period in the consolidated statements of operations (see Note 5). Allocation of the Purchase Consideration The acquisition of Shire’s MRT Program was accounted for in accordance with the acquisition method of accounting for business combinations. Acquisition-related costs totaling $3.0 million were expensed to general and administrative expenses as incurred. Such acquisition-related costs included $0.5 million for the services of the investment bank that facilitated the acquisition payable in shares of the Company’s common stock, which was satisfied in December 2017 through the Company’s issuance of 70,866 shares of common stock. The total consideration transferred was allocated to the tangible and identifiable intangible assets acquired based on their estimated fair values as follows (in thousands): Identifiable intangible assets $ 106,907 Property and equipment 2,416 Deferred tax assets 1,308 Deferred tax liabilities (18,520 ) Valuation allowance for deferred tax assets (1,308 ) Goodwill 21,359 Total purchase price consideration $ 112,162 Identifiable intangible assets acquired in the acquisition consisted of IPR&D and a lease-based asset. The IPR&D included ongoing projects that could further the Company’s preclinical and clinical development activities related to CF, OTC and other potential rare diseases. The lease-based intangible asset related to the below-market rental expense that the Company was expected to benefit from over the remaining lease period at one of its leased facilities. The IPR&D was determined to be indefinite-lived, and the lease-based intangible asset was determined to be definite-lived, with an estimated useful life of 1.5 years. The fair values of the identifiable intangible assets as of the acquisition date were as follows (in thousands): In-process research and development — MRT $ 45,992 In-process research and development — CF 42,291 In-process research and development — OTC 18,559 Lease agreement 65 Total identifiable intangible assets $ 106,907 The fair value of the IPR&D assets acquired was estimated by the Company at the acquisition date based, in part, on the results of the third-party valuation. The third-party valuation was prepared using the multi-period excess earnings method (“MPEEM”), a form of the income approach, which assumes the fair value of an intangible asset is equal to the present value of the incremental risk-adjusted after-tax cash flows attributable only to each IPR&D intangible asset. The MPEEM determined the after-tax cash flows, adjusted for contributory charges and cumulative probabilities of technical success. The probability-adjusted cash flows were then discounted to present value by the selected discount rate and added to the tax amortization benefit to determine the fair value. The key assumptions used in this model were net revenue projections, phase of development assumptions and discount rates. Upon commencement of the Sanofi Agreement, the IPR&D - MRT intangible asset was reclassified from indefinite-lived to definite-lived intangible assets and the Company began amortization of this intangible asset. Amortization will be recorded over an estimated eight-year period based on an economic consumption model. For the year ended December 31, 2018, the Company recorded amortization expense of $0.4 million related to the definite-lived IPR&D - MRT intangible asset. The estimated aggregate amortization expense for each of the five succeeding fiscal years is $3.2 million, $9.7 million, $10.5 million, $5.3 million and $2.0 million for the years ended December 31, 2019, 2020, 2021, 2022 and 2023, respectively. A deferred tax liability of $18.5 million was recorded as part of the business combination for the non-deductible portion of the indefinite-lived IPR&D acquired. As part of the business combination, the Company also recorded $1.3 million of acquired deferred tax assets related to depreciation of property and equipment, but recorded those with a full valuation allowance due to the uncertainty of realizing a benefit from those assets. The excess of the fair value of the consideration transferred over the fair value of identifiable assets acquired in the acquisition was allocated to goodwill in the amount of $21.4 million. Goodwill resulting from the acquisition was allocated to the Company’s single reporting unit and was largely attributed to the synergies and economies of scale expected from combining the research and operations of the MRT Program and the Company. Substantially all of the goodwill recorded as part of the MRT Program acquisition is not deductible for U.S. federal income tax purposes. The results of operations of the MRT Program business have been included in the Company’s consolidated statements of operations from the acquisition date. The operations of the MRT Program business were fully integrated into the Company’s operations and no separate financial results of the business were maintained. On June 7, 2018, the Company and Shire entered into an amendment to the Shire Agreement to align certain terms of the Shire Agreement with the collaboration and license agreement that the Company entered into with Sanofi on June 8, 2018. Pursuant to this amendment, an mRNA vaccine that is developed pursuant to the Company’s collaboration with Sanofi will be considered an MRT Product if it includes an MRT compound having an mRNA sequence that encodes a protein that is from, or that binds to, an infectious disease pathogen in a field that has been licensed by the Company to Sanofi. Pursuant to the amended Shire Agreement, the Company is obligated to make milestone payments of $10.0 million for each non-CF MRT Product upon the first commercial sale of a non-CF MRT Product; provided that such milestone payments will only be due once for any two non-CF MRT Products that contain the same MRT compounds or once per non-CF MRT Product that is a vaccine developed under the Company’s collaboration with Sanofi. The Company has concluded that this amendment will not affect the contingent purchase consideration recorded for accounting purposes. |
Fair Value of Financial Assets
Fair Value of Financial Assets and Liabilities | 12 Months Ended |
Dec. 31, 2018 | |
Fair Value Disclosures [Abstract] | |
Fair Value of Financial Assets and Liabilities | 5. Fair Value of Financial Assets and Liabilities The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands): Fair Value Measurements as of December 31, 2018 Using: Level 1 Level 2 Level 3 Total Assets: Money market funds $ — $ 23,318 $ — $ 23,318 U.S. government agency bonds — 88,904 — 88,904 $ — $ 112,222 $ — $ 112,222 Liabilities: Contingent consideration $ — $ — $ 103,642 $ 103,642 $ — $ — $ 103,642 $ 103,642 Fair Value Measurements as of December 31, 2017 Using: Level 1 Level 2 Level 3 Total Assets: Money market funds $ — $ 28,636 $ — $ 28,636 U.S. government agency bonds — 9,997 — 9,997 $ — $ 38,633 $ — $ 38,633 Liabilities: Contingent consideration $ — $ — $ 81,009 $ 81,009 $ — $ — $ 81,009 $ 81,009 During the years ended December 31, 2018 and 2017, there were no transfers between Level 1, Level 2 and Level 3. Cash equivalents as of December 31, 2018 and 2017 consisted of money market funds totaling $23.3 million and $28.6 million, respectively. The money market funds were valued using inputs observable in active markets for similar securities, which represent a Level 2 measurement in the fair value hierarchy. The Company’s short-term investments as of December 31, 2018 and 2017 consisted of U.S. government agency bonds and were classified as available-for-sale securities. The U.S. government agency bonds were valued using inputs observable in active markets for similar securities, which represent a Level 2 measurement in the fair value hierarchy. As of December 31, 2018, the Company’s short-term investments had an amortized cost of $88.7 million, an unrealized loss of $0.2 million and a fair value of $88.9 million. All of these securities have a maturity of one year or less. Valuation of Contingent Consideration The contingent consideration liability related to the acquisition of the MRT Program was classified as Level 3 measurement within the fair value hierarchy and includes the potential future milestone and earnout payments that may be due by the Company to Shire (see Note 4) and prior to the IPO, an anti-dilution liability with respect to shares issuable by the Company to Shire upon a qualified financing event (see Note 4). The fair value of the liability to make potential future milestone and earnout payments was estimated by the Company at each reporting date based, in part, on the results of a third-party valuation using a discounted cash flow analysis based on various assumptions, including the probability of achieving specified events, discount rates, and the period of time until earnout payments are payable and the conditions triggering the milestone payments are met. The actual settlement of contingent consideration could differ from current estimates based on the actual occurrence of these specified events. The fair value of the anti-dilution liability was estimated by the Company at each reporting date based, in part, on the results of a third-party valuation using the PWERM, which considers as inputs the probability of occurrence of events that would trigger the issuance of shares, the expected timing of such events, the expected value of the contingently issuable equity upon the occurrence of a triggering event and a risk-adjusted discount rate. The following tables presents the unobservable inputs and fair value of the components of the contingent consideration (dollar amounts in thousands): Unobservable Inputs at December 31, 2018 and 2017 Fair Value at Projected Year December 31, Discount Rate of Payment 2018 2017 Earnout payments 14.5% - 15.0% 2025 - 2039 $ 94,999 $ 72,896 Milestone payments 14.5% - 15.0% 2025 - 2030 8,643 6,817 Anti-dilution rights 1.39% - 1.64% N/A — 1,296 $ 103,642 $ 81,009 The following table presents a roll-forward of the total acquisition-related contingent consideration liability (in thousands): Fair Value Balance as of December 31, 2017 $ 81,009 Change in fair value of contingent consideration 25,020 Issuance of common stock in full settlement of contingent consideration anti-dilution liability (2,387 ) Balance as of December 31, 2018 $ 103,642 The increase in the fair value of contingent consideration during the year ended December 31, 2018 was primarily due to the continued progress of MRT5005, including the initiation in May 2018 of the Company’s Phase 1/2 clinical trial of MRT5005 for the treatment of patients with CF, the continued advancement of MRT5201 for the treatment of patients with OTC deficiency, the IND for which has been placed on clinical hold by the FDA, the time value of money due to the passage of time, as well as a decrease in the discount rate. In December 2017, as a result of the Company’s issuance and sale of 21,202,710 shares of Series C redeemable convertible preferred stock at that same time (see Note 8), the Company issued to Shire 1,079,765 shares of common stock, with an aggregate fair value of $8.0 million, pursuant to the anti-dilution rights conveyed to Shire in the Shire Agreement (see Note 4). The shares issued to Shire were in partial settlement of the Company’s anti-dilution contingent consideration liability that was recorded in its purchase accounting for the MRT Program in December 2016 and reflected as current portion of contingent consideration on the Company’s consolidated balance sheet as of December 31, 2017. The Company’s obligation related to these anti-dilution rights remained in effect until the Company consummated an additional equity financing of $7.0 million. After giving effect to the closing of the Company’s IPO, which satisfied the Subsequent Financing requirement (see Note 4), the Company issued an additional 183,619 shares of common stock to Shire in full satisfaction of the Company’s anti-dilution obligations to Shire. |
Property and Equipment, Net
Property and Equipment, Net | 12 Months Ended |
Dec. 31, 2018 | |
Property Plant And Equipment [Abstract] | |
Property and Equipment, Net | 6. Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): December 31, 2018 2017 Laboratory equipment $ 7,012 $ 5,382 Computer equipment 686 481 Office equipment 836 249 Leasehold improvements 5,635 1,131 Construction in progress 959 2,591 15,128 9,834 Less: Accumulated depreciation and amortization (4,883 ) (3,056 ) $ 10,245 $ 6,778 Depreciation and amortization expense related to property and equipment was $2.4 million and $1.5 million for the years ended December 31, 2018 and 2017, respectively. Construction in progress recorded as of December 31, 2017 primarily related to in-process construction of leasehold improvements, which were transferred to leasehold improvements in April 2018 upon completion. |
Accrued Expenses
Accrued Expenses | 12 Months Ended |
Dec. 31, 2018 | |
Payables And Accruals [Abstract] | |
Accrued Expenses | 7. Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, 2018 2017 Accrued employee compensation and benefits $ 2,933 $ 2,252 Accrued external research and development expenses 1,901 1,115 Accrued consultant and professional fees 977 1,130 Other 736 1,391 $ 6,547 $ 5,888 |
Redeemable Convertible Preferre
Redeemable Convertible Preferred Stock | 12 Months Ended |
Dec. 31, 2018 | |
Temporary Equity Disclosure [Abstract] | |
Redeemable Convertible Preferred Stock | 8. Redeemable Convertible Preferred Stock As of December 31, 2018 and 2017, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue no shares and 145,833,064 shares, respectively, of redeemable convertible preferred stock. As of December 31, 2017, the Company had 36,194,026 shares of Series A redeemable convertible preferred stock (the “Series A preferred stock”), 59,133,987 shares of Series B redeemable convertible preferred stock (the “Series B preferred stock”) and 46,960,279 shares of Series C redeemable convertible preferred stock (the “Series C preferred stock”) issued and outstanding. The Series A preferred stock, Series B preferred stock and Series C preferred stock were redeemable and convertible by the holders under specified conditions. The redeemable convertible preferred stock is classified outside of stockholders’ equity (deficit) because the shares contained redemption features that are not solely within the control of the Company. The Series A preferred stock, Series B preferred stock and Series C preferred stock are collectively referred to as the “Redeemable Convertible Preferred Stock.” In December 2017, the Company issued and sold 21,202,710 shares of Series C preferred stock at a price of $1.98 per share for aggregate proceeds of $41.9 million, net of issuance costs of $0.1 million. Upon issuance of each class of Redeemable Convertible Preferred Stock, the Company assessed the embedded conversion and liquidation features of the securities and determined that such features did not require the Company to separately account for these features. The Company also concluded that no beneficial conversion feature existed upon the issuance date of each class of Redeemable Convertible Preferred Stock or as of December 31, 2017. Upon the closing of the Company’s IPO on July 2, 2018, all then-outstanding shares of Redeemable Convertible Preferred Stock converted into an aggregate of 25,612,109 shares of common stock according to their terms. As of December 31, 2018, there were no shares of Redeemable Convertible Preferred Stock authorized, issued or outstanding. As of December 31, 2017, Redeemable Convertible Preferred Stock consisted of the following (in thousands, except share amounts): December 31, 2017 Preferred Shares Authorized Preferred Shares Issued and Outstanding Carrying Value Liquidation Preference Common Stock Issuable Upon Conversion Series A preferred stock 36,194,026 36,194,026 $ 36,194 $ 36,194 6,514,986 Series B preferred stock 59,133,987 59,133,987 64,002 63,199 10,644,210 Series C preferred stock 50,505,051 46,960,279 92,700 92,981 8,452,913 145,833,064 142,288,292 $ 192,896 $ 192,374 25,612,109 The holders of the Redeemable Convertible Preferred Stock had the following rights and preferences prior to the conversion on Preferred Stock into common stock upon the completion of the Company’s IPO: Voting The holders of Redeemable Convertible Preferred Stock were entitled to vote, together with the holders of common stock, on all matters submitted to stockholders for a vote and had the right to vote the number of shares equal to the number of shares of common stock into which each share of Redeemable Convertible Preferred Stock could convert on the record date for determination of stockholders entitled to vote. In addition, the holders of Series A preferred stock were entitled to elect two directors of the Company, and the holders of Series B preferred stock were entitled to elect one director of the Company. Conversion Each share of Redeemable Convertible Preferred Stock was convertible, at the option of the holder, at any time after the date of issuance. In addition, each share of Redeemable Convertible Preferred Stock would be automatically converted into shares of common stock at the applicable conversion ratio then in effect (i) upon the closing of a firm-commitment public offering resulting in at least $50.0 million of gross proceeds to the Company at a price of at least $13.20 per share of common stock, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization, or (ii) upon the written consent of the holders of at least 60% of the then-outstanding shares of Redeemable Convertible Preferred Stock, voting together as a single class. The conversion ratio of each series of Redeemable Convertible Preferred Stock was determined by dividing the Original Issue Price of each series by the Conversion Price of each series. The Original Issue Price per share was $1.00 for Series A preferred stock, $1.0593 for Series B-1 preferred stock, $1.00 for Series B-2 preferred stock, $1.0305 for Series B-3 preferred stock, $1.0330 for Series B-4 preferred stock, $1.0381 for Series B-5 preferred stock, $1.0513 for Series B-6 preferred stock, $1.0426 for Series B-7 preferred stock, $1.08 for Series B-8 preferred stock and $1.98 for Series C preferred stock. The Series B-1, Series B-2, Series B-3, Series B-4, Series B-5, Series B-6, Series B-7 and Series B-8 preferred stock are referred to collectively as “Series B preferred stock.” Upon completion of the Company’s IPO, each share of each series of Redeemable Convertible Preferred Stock was convertible into shares of common stock on a 5.5555-for-one basis. The Conversion Price per shares at issuance was $5.5555 for Series A preferred stock, $5.8849 for Series B-1 preferred stock, $5.5555 for Series B-2 preferred stock, $5.7249 for Series B-3 preferred stock, $5.7388 for Series B-4 preferred stock, $5.7672 for Series B-5 preferred stock, $5.8405 for Series B-6 preferred stock, $5.7922 for Series B-7 preferred stock, $5.9999 for Series B-8 preferred stock and $10.9999 for Series C preferred stock, each subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization and other adjustments as set forth in the Company’s certificate of incorporation, as amended and restated. Dividends The holders of the Redeemable Convertible Preferred Stock were entitled to receive noncumulative dividends when, as and if declared by the board of directors. The Company could not pay any dividends on shares of common stock of the Company unless the holders of Redeemable Convertible Preferred Stock then outstanding simultaneously receive dividends at the same rate and same time as dividends are paid with respect to common stock. Through December 31, 2018 and 2017, no cash dividends have been declared or paid. Liquidation In the event of any voluntary or involuntary liquidation, dissolution or winding up of the Company or Deemed Liquidation Event (as defined below), the holders of the then-outstanding Redeemable Convertible Preferred Stock were entitled to receive, in preference to any distributions to the common stockholders, an amount per share equal to the Original Issue Price per share of each respective share of Redeemable Convertible Preferred Stock, plus all dividends declared but unpaid on such shares. In the event that the assets available for distribution to the Company’s stockholders were not sufficient to permit payment to the holders of Redeemable Convertible Preferred Stock in the full amount to which they were entitled, the assets available for distribution would be distributed on a pro rata basis among the holders of the Redeemable Convertible Preferred Stock in proportion to the respective amounts otherwise payable in respect of the shares of Redeemable Convertible Preferred Stock. After the payments were made in full to the holders of Redeemable Convertible Preferred Stock, to the extent available, the remaining amounts would be distributed among the holders of the Redeemable Convertible Preferred Stock and common stock, pro rata based on the number of shares held by each holder. Unless the holders of at least 60% of the then-outstanding Redeemable Convertible Preferred Stock, voting together as a single class, elected otherwise, a Deemed Liquidation Event would include a merger or consolidation (other than one in which stockholders of the Company own a majority by voting power of the outstanding shares of the surviving or acquiring corporation) or a sale, lease, transfer, exclusive license or other disposition of all or substantially all of the assets of the Company. Redemption At the written election of at least 60% of the holders of Redeemable Convertible Preferred Stock, voting together as a single class, the shares of Redeemable Convertible Preferred Stock outstanding were redeemable, at any time on or after December 22, 2021, in three equal annual installments commencing no more than 60 days after written notice, in an amount equal to the Original Issue Price per share of each series of Redeemable Convertible Preferred Stock plus all declared but unpaid dividends thereon. |
Preferred Stock
Preferred Stock | 12 Months Ended |
Dec. 31, 2018 | |
Equity [Abstract] | |
Preferred Stock | 9. Preferred Stock On July 2, 2018, in connection with the closing of the Company’s IPO, the Company filed its restated certificate of incorporation, which authorizes the Company to issue up to 10,000,000 shares of preferred stock, $0.001 par value per share. There are no shares of preferred stock outstanding as of December 31, 2018. |
Common Stock
Common Stock | 12 Months Ended |
Dec. 31, 2018 | |
Equity [Abstract] | |
Common Stock | 10. Common Stock As of December 31, 2017, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue 236,092,611 shares of common stock, $0.001 par value per share. On July 2, 2018, the Company filed it restated certificate of incorporation, which authorizes the Company to issue up to 200,000,000 shares of common stock, $0.001 par value per share. Each share of common stock entitles the holder to one vote for each share of common stock held. Common stockholders are entitled to receive dividends, as declared by the board of directors. These dividends are subject to the preferential dividend rights of the holders of the Company’s preferred stock. Through December 31, 2018 and 2017, no cash dividends have been declared or paid. As of December 31, 2017, the Company had reserved 32,115,490 shares of common stock for the conversion of outstanding shares of Redeemable Convertible Preferred Stock (see Note 9), the exercise of outstanding stock options (see Note 11) and the number of shares remaining available for future issuance under the 2016 Stock Incentive Plan (see Note 11). Upon completion of the Company’s IPO on July 2, 2018, all shares of Redeemable Convertible Preferred Stock converted to common stock. |
Incentive Stock Options and Res
Incentive Stock Options and Restricted Stock | 12 Months Ended |
Dec. 31, 2018 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Incentive Stock Options and Restricted Stock | 11. Incentive Stock Options and Restricted Stock 2018 Equity Incentive Plan On March 7, 2018, the Company’s board of directors, subject to stockholder approval, adopted, and on June 15, 2018, its stockholders approved, the 2018 Equity Incentive Plan (the “2018 Plan”), which became effective on June 27, 2018. The 2018 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. The number of shares initially reserved for issuance under the 2018 Plan is the sum of 2,512,187, plus the number of shares (up to 1,013,167 shares) equal to the sum of (i) the number of shares remaining available for issuance under the 2016 Stock Incentive Plan, as amended, (the “2016 Plan”), upon the effectiveness of the 2018 Plan, which was 360,514 shares, and (ii) the number of shares of common stock subject to outstanding awards under the 2016 Plan that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right. The number of shares of common stock that may be issued under the 2018 Plan will automatically increase on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2019 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2028, equal to the lowest of (i) 3,349,582 shares, (ii) 4% of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. The shares of common stock underlying any awards that are forfeited, canceled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, repurchased or are otherwise terminated by the Company under the 2018 Plan will be added back to the shares of common stock available for issuance under the 2018 Plan. During the year ended December 31, 2018, option awards to purchase 203,176 shares of common stock were granted under the 2018 Plan. Shares that are expired, terminated, surrendered or canceled under the 2018 Plan without having been exercised will be available for future grants of awards. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards. The 2018 Plan is administered by the board of directors. The exercise prices, vesting periods and other restrictions are determined at the discretion of the board of directors, except that the exercise price per share of options may not be less than 100% of the fair market value of the common stock on the date of grant. Stock options awarded under the 2018 Plan expire 10 years after the grant date, unless the board of directors sets a shorter term. Awards granted to employees, officers, members of the board of directors and consultants typically vest over a four-year period. Unvested stock options are forfeited upon the recipient ceasing to provide services to the Company. 2018 Employee Stock Purchase Plan On March 7, 2018, the Company’s board of directors, subject to stockholder approval, adopted, and on June 15, 2018, its stockholders approved the 2018 Employee Stock Purchase Plan (the “2018 ESPP”), which became effective on June 27, 2018. A total of 418,697 shares of common stock were initially reserved for issuance under this plan. The number of shares of common stock that may be issued under the 2018 ESPP will automatically increase on the first day of each fiscal year, beginning with the fiscal year commencing on January 1, 2019 and continuing for each fiscal year until, and including, the fiscal year commencing on January 1, 2029, equal to the lowest of (i) 837,395 shares, (ii) 1% of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. As of December 31, 2018, no shares had been issued under the 2018 ESPP. 2016 Stock Incentive Plan The 2016 Plan provided for the Company to issue equity awards to employees, officers and directors, consultants and advisors. Under the 2016 Plan, the Company was allowed to grant stock options, stock appreciation rights, restricted stock and restricted stock units. Shares that are expired, terminated, surrendered or canceled under the 2016 Plan without having been exercised will be available for future grants of awards under the 2018 Plan. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards under the 2018 Plan. The 2016 Plan was administered by the board of directors. The exercise prices, vesting periods and other restrictions were determined at the discretion of the board of directors, except that the exercise price per share of options may not be less than 100% of the fair market value of the common stock on the date of grant. Stock options awarded under the 2016 Plan expire 10 years after the grant date, unless the board of directors set a shorter term. Stock options and restricted stock granted to employees, officers, members of the board of directors and consultants typically vest over a four-year period. Upon the effectiveness of the 2018 Plan on June 27, 2018, no further awards will be made under the 2016 Plan. Awards outstanding under the 2016 Plan will continue to be governed by their existing terms. During the year ended December 31, 2018, option awards to purchase 1,966,114 shares of common stock were granted under the 2016 Plan. Stock Options The following table summarizes the Company’s stock option activity since December 31, 2017 (in thousands, except share and per share amounts): Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Intrinsic Value (in years) Outstanding as of December 31, 2017 4,364,916 $ 7.17 9.79 $ 977 Granted 2,169,290 $ 8.82 Exercised (49,459 ) $ 5.62 Forfeited (248,741 ) $ 6.62 Outstanding as of December 31, 2018 6,236,006 $ 7.78 8.74 $ 1,104 Vested as of December 31, 2018 1,827,004 $ 7.16 7.95 $ 632 Vested and expected to vest as of December 31, 2018 6,236,006 $ 7.78 8.74 $ 1,104 Vested as of December 31, 2017 661,593 $ 7.04 9.72 $ 231 Vested and expected to vest as of December 31, 2017 4,364,916 $ 7.17 9.79 $ 977 The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock for those options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised during the year ended December 31, 2018 was $0.1 million. There were no options exercised during the year ended December 31, 2017. The weighted average grant-date fair value per share of stock options granted was $5.95 and $4.10 during the years ended December 31, 2018 and 2017, respectively. The total fair value of options vested during the years ended December 31, 2018 and 2017 was $4.9 million and $2.6 million, respectively. Stock Option Valuation The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. The Company historically has been a private company and lacks company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted to employees and directors: Year Ended December 31, 2018 2017 Risk-free interest rate 2.81 % 2.15 % Expected term (in years) 6.0 6.0 Expected volatility 75.5 % 59.0 % Expected dividend yield 0 % 0 % The following table presents the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted to a non-employee: Year Ended December 31, 2017 Risk-free interest rate 2.08 % Expected term (in years) 10.0 Expected volatility 60.9 % Expected dividend yield 0 % During the year ended December 31, 2018, the Company did not grant options to non-employees. Restricted Common Stock The following table summarizes the Company’s restricted stock activity since December 31, 2017: Number of Shares Weighted Average Grant-Date Fair Value Unvested restricted common stock outstanding as of December 31, 2017 526,478 $ 1.14 Forfeited restricted common stock (2,446 ) $ 1.28 Vested restricted common stock (304,884 ) $ 1.04 Unvested restricted common stock outstanding as of December 31, 2018 219,148 $ 1.27 The total fair value of restricted common stock vested during the years ended December 31, 2018 and 2017 was $0.3 million and $0.4 million, respectively, which the Company recorded as stock-based compensation during those periods. Stock-Based Compensation Stock-based compensation expense was classified in the consolidated statements of operations as follows (in thousands): Year Ended December 31, 2018 2017 Research and development expenses $ 3,756 $ 1,886 General and administrative expenses 3,577 1,794 $ 7,333 $ 3,680 Included in research and development stock-based compensation expense for the year ended December 31, 2018 was $0.3 million related to the modification of options in connection with the resignation of the Company’s former Chief Scientific Officer (“CSO”). In connection with this resignation, the Company entered into a separation agreement with the former CSO. Under the terms of the separation agreement, vesting of options for the purchase of 72,871 shares of common stock held by the former CSO was accelerated with no change to the exercise price of such options. Stock options for the purchase of 204,353 shares of common stock, representing all of the options held by the former CSO as of the date of his resignation, are exercisable for one year following his resignation. As of December 31, 2018, total unrecognized compensation cost related to the unvested stock-based awards was $19.6 million, which is expected to be recognized over weighted average periods of 2.6 years. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2018 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | 12. Income Taxes On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was signed into United States law. The Tax Act includes a number of changes to existing tax law, including, among other things, a permanent reduction in the top marginal federal corporate income tax rate from 35% to a flat rate of 21%, effective as of January 1, 2018, as well as limitation of the deduction for net operating losses to 80% of annual taxable income and elimination of net operating loss carrybacks. The enactment of the Tax Act resulted in the Company recording a net income tax benefit of $6.1 million in the year ended December 31, 2017. The $6.1 million net income tax benefit consisted of (i) the remeasurement of the deferred tax liabilities for the Company’s indefinite-lived intangible assets due to the tax rate reduction, which resulted in a corresponding income tax benefit of $3.7 million, and (ii) a reduction in the valuation allowance for deferred tax assets related to deductible temporary differences that will generate unlimited net operating loss carryforwards when they reverse in future periods, which resulted in a corresponding income tax benefit of $2.4 million. No adjustments to the provisional amounts recorded as of December 31, 2017 were recorded during the year ended December 31, 2018. During 2017, the Company recorded tax charges for the impact of the Tax Act effects using the current available information and technical guidance on the interpretations of the Tax Act. As permitted by SEC Staff Accounting Bulletin 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act, the Company recorded provisional estimates and have subsequently finalized our accounting analysis based on the guidance, interpretations and data available as of December 31, 2018 with no material changes to our estimates. Income Taxes During the year ended December 31, 2018, the Company recognized an income tax benefit of $5.6 million, which resulted from a reduction in the deferred tax liabilities recorded as part of the Company’s acquisition of the MRT Program. The reduction in the deferred tax liabilities during the year ended December 31, 2018 resulted from an increase in the tax basis of the indefinite-lived IPR&D recorded in the acquisition. During the year ended December 31, 2017, the Company recognized an income tax benefit of $12.5 million, consisting of (i) a $6.4 million benefit due to a reduction of the same amount in the deferred tax liabilities recorded as part of the Company’s acquisition of the MRT Program (see Note 4) and (ii) a $6.1 million benefit resulting from the impact of the Tax Act. The reduction in the deferred tax liabilities during the year ended December 31, 2017 resulted from an increase in 2017 in the tax basis of the indefinite-lived IPR&D recorded in the acquisition. All of the Company’s operating losses since inception have been generated in the United States. A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2018 2017 U.S. federal statutory income tax rate (21.0 )% (34.0 )% State income taxes, net of federal benefit (6.9 ) (5.4 ) Research and development tax credits and orphan drug credit (5.5 ) (4.2 ) Stock-based compensation 0.5 1.5 Other permanent differences 0.3 0.4 Remeasurement of deferred taxes due to the Tax Act — 15.9 Change in deferred tax asset valuation allowance 27.7 10.0 Other (0.4 ) — Effective income tax rate (5.3 )% (15.8 )% Components of the Company’s deferred tax assets and liabilities were as follows (in thousands): December 31, 2018 2017 Deferred tax assets: Net operating loss carryforwards $ 50,917 $ 32,524 Research and development tax credit and orphan drug credit carryforwards 13,581 6,372 Depreciation and amortization 2,380 2,025 Accrued expenses and other 2,894 1,090 Total deferred tax assets 69,772 42,011 Deferred tax liabilities: Indefinite-lived intangible assets (2,109 ) (8,445 ) Total deferred tax liabilities (2,109 ) (8,445 ) Valuation allowance (68,143 ) (39,605 ) Net deferred tax liabilities $ (480 ) $ (6,039 ) As of December 31, 2018, the Company had federal net operating loss carryforwards of $190.8 million, of which $122.1 million will, if not utilized, begin to expire in 2031, and state net operating loss carryforwards of $171.7 million, which will, if not utilized, begin to expire in 2031. As of December 31, 2018, the Company had federal and state research and development tax credits carryforwards of $5.1 million and $2.0 million, respectively, which will, if not utilized, begin to expire in 2032 and 2028, respectively, and orphan drug tax credit carryforwards of $6.6 million, which will, if not utilized, begin to expire in 2037. The Company also has state investment tax credit carryforwards of $0.4 million, which will, if not utilized, begin to expire in 2019. Utilization of the net operating loss carryforwards and research and development tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986, as amended, due to ownership changes that have occurred previously or that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain stockholders or public groups in the stock of a corporation by more than 50% over a three-year period. The Company has not conducted a study to assess whether an ownership change has occurred or whether there have been multiple ownership changes since inception due to the significant complexity and cost associated with such a study. If the Company has experienced an ownership change, as defined by Section 382, at any time since inception, utilization of the net operating loss carryforwards or research and development tax credit carryforwards would be subject to an annual limitation under Section 382, which is determined by first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term tax-exempt rate, and then could be subject to additional adjustments, as required. Any limitation may result in expiration of a portion of the net operating loss carryforwards or research and development tax credit carryforwards before utilization. Further, until a study is completed by the Company and any limitation on the use of net operating loss carryforwards is known, no amounts are being presented as an uncertain tax position. In addition, the Company has not conducted a study of its research and development tax credit carryforwards. This study may result in an adjustment to the Company’s research and development tax credit carryforwards. Until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position. The Company has evaluated the positive and negative evidence bearing upon its ability to realize the deferred tax assets. Management has considered the Company’s history of cumulative net losses incurred since inception and its lack of commercialization of any products or generation of any revenue from product sales since inception and has concluded that it is more likely than not that the Company will not realize all of the benefits of the deferred tax assets. As of December 31, 2017, a full valuation allowance had been established against the deferred tax assets with the exception of $2.4 million of deferred tax assets related to deductible temporary differences that will generate unlimited net operating loss carryforwards when they reverse in future periods. At December 31, 2018, the Company maintained a full valuation allowance with the exception of $0.8 million related primarily to indefinite-lived net operating loss carryforwards. Management reevaluates the positive and negative evidence at each reporting period. Changes in the valuation allowance for deferred tax assets during the years ended December 31, 2018 and 2017 related primarily to the increase in net operating loss carryforwards and research and development tax credit carryforwards in 2018 and 2017, and the impact of the Tax Act in 2017, and were as follows (in thousands): Year Ended December 31, 2018 2017 Valuation allowance at beginning of year $ (39,605 ) $ (31,729 ) Decreases recorded as benefit to income tax provision — 18,628 Increases recorded to income tax provision (28,538 ) (26,504 ) Valuation allowance at end of year $ (68,143 ) $ (39,605 ) In the year ended December 31, 2018, the increase in the valuation allowance of $28.5 million was driven primarily by the generation of federal and state net operating loss and tax credit carryforwards. In the year ended December 31, 2017, the decrease in the valuation allowance of $18.6 million consisted of (i) a $16.2 million decrease to offset the corresponding decrease in deferred tax assets remeasured at the lower federal income tax rate and (ii) a $2.4 million decrease due to deductible temporary differences that will generate unlimited net operating loss carryforwards when they reverse in future periods, both of which resulted from the enactment of the Tax Act. During the year ended December 31, 2017, in its assessment of the realizability of deferred tax assets, the Company concluded that $2.4 million of the $8.4 million of deferred tax liabilities recorded for indefinite-lived IPR&D as of December 31, 2017 could be considered a source of future taxable income for the realization of deferred tax assets. As a result, the Company did not use $6.0 million of the established deferred tax liabilities to reduce the valuation allowance recorded as of December 31, 2017 because the reversal of that portion of the deferred tax liabilities could not be assumed to occur. The Company had not recorded any amounts for unrecognized tax benefits as of December 31, 2018 and 2017. The Company files income tax returns in the U.S. and Massachusetts. The federal and state returns are generally subject to tax examinations for the tax years ended December 31, 2013 to the present. There are currently no pending tax examinations. To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the Internal Revenue Service and state tax authorities to the extent utilized in a future or prior period. The Company’s policy is to record interest and penalties related to income taxes as part of its income tax provision. |
Net Loss per Share
Net Loss per Share | 12 Months Ended |
Dec. 31, 2018 | |
Earnings Per Share [Abstract] | |
Net Loss per Share | 13. Net Loss per Share Net Loss per Share Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): Year Ended December 31, 2018 2017 Numerator: Net loss $ (97,395 ) $ (66,443 ) Accretion of redeemable convertible preferred stock to redemption value (644 ) (719 ) Net loss attributable to common stockholders $ (98,039 ) $ (67,162 ) Denominator: Weighted average common shares outstanding—basic and diluted 26,945,508 7,756,180 Net loss per share attributable to common stockholders—basic and diluted $ (3.64 ) $ (8.66 ) The Company excluded 372,301 shares and 733,134 shares of restricted common stock, presented on a weighted average basis, from the calculations of basic net loss per share attributable to common stockholders for the years ended December 31, 2018 and 2017, respectively, because those shares had not vested. The Company’s potentially dilutive securities, which include stock options, unvested restricted common stock and redeemable convertible preferred stock, have been excluded from the computation of diluted net loss per share attributable to common stockholders as the effect would be to reduce the net loss per share. Therefore, the weighted average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential shares of common stock, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Year Ended December 31, 2018 2017 Options to purchase common stock 6,236,006 4,364,916 Unvested restricted common stock 219,148 526,478 Redeemable convertible preferred stock (as converted to common stock) — 25,612,109 6,455,154 30,503,503 In addition to the potentially dilutive securities noted above, as of December 31, 2017, the Company was obligated to issue common stock to Shire upon the occurrence of specified events (see Notes 4 and 5). Because the necessary conditions for issuance of the shares had not been met as of December 31, 2017, the Company excluded these shares from the table above and from the calculations of diluted net loss per share for the year ended December 31, 2017. |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2018 | |
Commitments And Contingencies Disclosure [Abstract] | |
Commitments And Contingencies | 14. Commitments and Contingencies Lease Commitments The Company leases office and laboratory space under an operating lease that expires in April 2028. The Company recognizes rent expense on a straight-line basis over the respective lease period and has recorded deferred rent for rent expense incurred but not yet paid. The Company recorded rent expense of $3.0 million and $3.1 million during the years ended December 31, 2018 and 2017, respectively. In May 2015, the Company entered into an operating lease for office and laboratory space in Cambridge, Massachusetts, which was due to expire in May 2022. In connection with entering into this lease agreement, the Company issued a letter of credit collateralized by cash deposits totaling $1.0 million, which was reduced to $0.7 million in December 2017. These cash deposits are classified as restricted cash on the consolidated balance sheets. In September 2017, the Company and the lessor agreed to early terminate the lease as of April 2018 and the Company was relieved of its obligation to pay the remaining lease payments through the expiration date of the original lease. The Company vacated the leased space in April 2018 and the letter of credit was released during the third quarter of 2018. Pursuant to the Shire Agreement (see Note 4), in December 2016, the Company assumed an operating lease, due to expire in May 2018, for office and laboratory space in Lexington, Massachusetts. In January 2017, in connection with this lease agreement, the Company issued two letters of credit collateralized by cash deposits totaling $0.3 million, which were classified as restricted cash on the consolidated balance sheets. In November 2017, the lease was amended pursuant to which (i) the lease was extended by 12 months, commencing in June 2018 and expiring in May 2019, and (ii) the landlord was granted the option, at its sole discretion, to terminate the lease upon 90 days’ notice, provided that the expiration date will be no earlier than November 30, 2018. On June 22, 2018 the Company entered into a Termination and Surrender Agreement with the landlord relating to this lease subject to certain conditions. In July 2018, following receipt of a $0.3 million termination payment, the landlord released the Company from any further obligations under the lease. The Company vacated the leased space in June 2018 and the letters of credit were released during the third quarter of 2018. In June 2017, the Company entered into an operating lease for office and laboratory space at its new headquarters in Lexington, Massachusetts. Monthly lease payments include base rent charges of $0.2 million, which are subject to a 3% annual increase each year. The lease expires in April 2028. In June 2017, in connection with this lease agreement, the Company issued a letter of credit collateralized by cash deposits of $1.0 million, which are classified as restricted cash on the consolidated balance sheets as of December 31, 2018 and 2017. The following table summarizes the future minimum lease payments due under the Company’s operating leases as of December 31, 2018 (in thousands): Year Ending December 31, 2019 $ 2,534 2020 2,610 2021 2,688 2022 2,769 2023 2,852 2024 and thereafter 13,096 $ 26,549 Research, Supply and License Agreements Pursuant to the Shire Agreement (see Note 4), in December 2016, the Company was assigned and assumed several contracts related to the MRT Program. The material agreements that were assigned to and assumed by the Company in connection with the acquisition are described below. Roche Master Supply Agreement The Company is a party to a master supply agreement with Roche Diagnostics Corporation (“Roche”) pursuant to which Roche will custom manufacture certain products for the Company. The agreement requires the Company to purchase from Roche specified manufactured products and the related raw materials in an amount equal to the greater of (i) quantities of raw materials in the Company’s annual forecast to be purchased or (ii) 80% of the Company’s demand for products as the same or similar type (the “Purchase Commitment”). In June 2017, the Company exercised its option under the agreement to extend the agreement through December 31, 2024. On September 28, 2018, the Company and Roche amended the agreement to remove and replace the Purchase Commitment for certain manufactured products and related raw materials supplied by Roche. The agreement, as amended, specifies a minimum purchase requirement for certain custom manufactured products. As of December 31, 2018, the Company’s purchase commitments under the agreement totaled $24.0 million, with $9.6 million committed as payments in 2019, $0.5 million committed as payments in 2020 and $3.5 million committed as payments each year from 2021 to 2024. Research and development expenses related to this agreement totaled $5.0 million and $1.8 million during the years ended December 31, 2018 and 2017, respectively. MIT Research Agreement The Company is a party to a research agreement with the Massachusetts Institute of Technology (“MIT”) pursuant to which the Company is obligated to reimburse MIT in an amount up to $3.1 million for specified direct and indirect costs incurred through October 2019 in specified research activities conducted for the Company. As of December 31, 2018 and 2017, the Company had paid MIT $2.5 million and $1.0 million, respectively, of the total committed amount. As of December 31, 2018, the Company’s research commitments under the agreement totaled $0.7 million. Research and development expenses related to this agreement totaled $1.2 million during each of the years ended December 31, 2018 and 2017. As of December 31, 2018 and 2017, amounts payable by the Company under the agreement totaled $0 and $0.2 million, respectively. As amended, the agreement expires in October 2019 and may be extended thereafter by mutual agreement of the parties. MIT Exclusive Patent License Agreement The Company is a party to an exclusive patent license agreement with MIT pursuant to which the Company received an exclusive license under the licensed patent rights to develop, manufacture and commercialize any product containing both (i) any RNA sequences, including mRNA, that encode a protein or peptide suitable for human therapeutic use which may include operably linked non-coding sequences that facilitate translation of the coding portion of such RNA sequence, but such non-coding sequences do not include nucleic acids that function through an RNA interface mechanism or transcriptional activation mechanism (the “coding RNA component”), and (ii) products covered by the licensed patent rights (the “lipid products”). A product containing both a coding RNA component and a lipid product is referred to as a “licensed product.” Under the licensed patent rights, the Company is permitted to develop, manufacture and commercialize the licensed products for the delivery of coding RNA components to treat disease in humans. The Company has the right to grant sublicenses under this license. The patent rights licensed to the Company by MIT include claims that cover the Company’s customized lipid-based nanoparticles used for delivery of coding RNA components in its MRT platform and MRT5201. Under the license agreement, the Company is obligated to make annual license maintenance payments to MIT, payable on January 1 of each calendar year, of up to $0.2 million, which may be credited against royalties subsequently due on net sales of licensed products earned in the same calendar year. During each of the years ended December 31, 2018 and 2017, the Company paid annual license maintenance fees of $0.1 million to MIT. The Company is also obligated to make milestone payments to MIT aggregating up to $1.375 million upon the achievement of specified clinical and regulatory milestones with respect to each licensed product and $1.250 million upon the Company’s first commercial sale of each licensed product, and to pay royalties of a low-single-digit percentage to MIT based on the Company’s, and any of its affiliates’ and sublicensees’, net sales of licensed products. The royalties are payable on a product-by-product and country-by-country basis, and may be reduced in specified circumstances. The Company’s obligation to make royalty payments extends with respect to a licensed product in a country until the expiration of the last-to-expire patent or patent application licensed from MIT covering the licensed product in the country. In addition, the Company is obligated to pay MIT a low-double-digit percentage of the portion of income from sublicenses that the Company ascribes to the MIT-licensed patents, excluding royalties on net sales and research support payments. In 2019, pursuant to such provision, the Company has agreed to pay $0.7 million to MIT as its share of sublicense income with respect to the upfront payment received under the Sanofi Agreement, which is recorded in accrued expenses on the Company’s consolidated balance sheet as of December 31, 2018. The amounts that the Company may owe to MIT will depend upon the relative value of the patents the Company licensed from MIT and sublicensed to Sanofi as compared to the other rights that the Company licensed to Sanofi. The determination of the relative value of such rights is subject to a process described in the Company’s license agreement with MIT (see Note 3). The agreement obligates the Company to use commercially reasonable efforts and expend a minimum amount of resources each year to develop licensed products in accordance with a development plan, and a development milestone timetable specified in the agreement; to use commercially reasonable efforts to commercialize licensed products; and upon commercialization, to make the licensed products reasonably available to the public. MIT has the right to terminate the agreement if the Company fails to pay amounts when due or otherwise materially breaches the agreement and fails to cure such nonpayment or breach within specified cure periods or in the event the Company ceases to carry on its business related to the agreement. In the event of a termination due to the Company’s breach caused by a due diligence failure of a licensed product, but where the Company has fulfilled its obligations with respect to a different licensed product, MIT may not terminate the agreement with respect to the different licensed product. MIT may immediately terminate the agreement if the Company or any of its affiliates brings specified patent challenges against MIT or assists others in bringing a patent challenge against MIT. The Company has the right to terminate the agreement for its convenience at any time on three months’ prior written notice to MIT and payment of all amounts due to MIT through the date of termination. The Company’s patent rights, and the rights of its affiliates and sublicensees, in specified licensed products may also terminate, if, after November 1, 2018, the Company, its affiliates or MIT receives a request from a third party to develop such licensed product for which the Company is unable to, within nine months of receiving notice of any such request, either demonstrate that the Company has initiated a fully funded project for the commercial development of such licensed product, and provide a business plan with acceptable milestones; demonstrate that the licensed product proposed by such third party would be competitive with a licensed product for which the Company has initiated a fully funded project; or enter into a sublicense agreement with such third party on commercially reasonable terms, and, in each case, MIT, in its sole discretion, grants a license to such third party for the specified patent rights. Research and development expenses related to this agreement totaled $0.1 million during each of the years ended December 31, 2018 and 2017. As of December 31, 2018 and 2017, amounts payable by the Company related to this agreement totaled $0.7 million and $0, respectively. Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company does not believe that the outcome of any claims under indemnification arrangements will have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of December 31, 2018 and 2017. Legal Proceedings The Company is not a party to any litigation and does not have contingency reserves established for any litigation liabilities. |
Related Party Transactions
Related Party Transactions | 12 Months Ended |
Dec. 31, 2018 | |
Related Party Transactions [Abstract] | |
Related Party Transactions | 15. Related Party Transactions Consulting Agreement with Daniel S. Lynch In 2012, the Company entered into a consulting agreement with Daniel S. Lynch, the chairman of the Company’s board of directors, for the provision of consulting, advisory and related services. Pursuant to the consulting agreement, as amended through March 2015, Mr. Lynch was entitled to base compensation of $100,000 per year and was eligible to receive an annual performance bonus of up to 25% of his base compensation. In June 2018, the Company’s board of directors approved a director compensation program that became effective on the effective date of the registration statement related to the Company’s IPO. The Company has not made any payments to Mr. Lynch under the consulting agreement since the approval of the director compensation program. During each of the years ended December 31, 2018 and 2017, the Company recorded general and administrative expenses of $0.1 million related to this agreement. During each of the years ended December 31, 2018 and 2017, the Company paid Mr. Lynch $0.1 million in connection with his services provided under the agreement. As of December 31, 2018 and 2017, amounts due under this agreement totaled $11,250 and $20,000, respectively, which were included in accrued expenses on the consolidated balance sheets. During the year ended December 31, 2017, the Company granted to Mr. Lynch stock options to purchase 85,170 shares of common stock, at an exercise price of $7.39 per share, which vest monthly over a four-year period. The stock options had a grant-date fair value of $4.06 per share and an aggregate fair value of $0.3 million. |
Costs Associated with Restructu
Costs Associated with Restructuring | 12 Months Ended |
Dec. 31, 2018 | |
Restructuring And Related Activities [Abstract] | |
Costs Associated with Restructuring | 16. Costs Associated with Restructuring In June 2017, the Company implemented a reorganization of its operations, which reduced its workforce by 17 positions in connection with a strategic realignment of resources aimed at better supporting the advancement of its MRT platform. The benefits provided to the employees as part of this reorganization were determined to be involuntary termination benefits provided under the terms of a one-time benefit arrangement pursuant to which employees were not required to provide future services to the Company. During the year ended December 31, 2017, the Company recorded employee severance charges of $0.5 million related to this restructuring, which were included in research and development expenses in the consolidated statements of operations. Changes in accrued restructuring costs were as follows (in thousands): Balance at December 31, 2016 $ — Charges 473 Payments (473 ) Balance at December 31, 2017 $ — |
Benefit Plans
Benefit Plans | 12 Months Ended |
Dec. 31, 2018 | |
Compensation And Retirement Disclosure [Abstract] | |
Benefit Plans | 17. Benefit Plans The Company has established a defined-contribution retirement plan under Section 401(k) of the Code. This plan covers all employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. Matching contributions to the plan may be made at the discretion of the Company’s board of directors. During the years ended December 31, 2018 and 2017, the Company contributed $0.3 million and $0.2 million, respectively, to the plan. |
Selected Quarterly Financial In
Selected Quarterly Financial Information (Unaudited) | 12 Months Ended |
Dec. 31, 2018 | |
Selected Quarterly Financial Information [Abstract] | |
Selected Quarterly Financial Information | 18. Selected Quarterly Financial Information (Unaudited) The following table contains quarterly financial information for 2018 and 2017 (in thousands, except per share amounts). The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Total Collaboration revenue $ — $ — $ 238 $ 1,182 $ 1,420 Total operating expenses 22,389 29,062 45,719 8,480 105,650 Loss from operations (22,389 ) (29,062 ) (45,481 ) (7,298 ) (104,230 ) Net loss (21,209 ) (27,503 ) (42,646 ) (6,037 ) (97,395 ) Net loss per share applicable to common stockholders—basic and diluted $ (2.35 ) $ (3.04 ) $ (0.97 ) $ (0.13 ) $ (3.64 ) 2017 First Quarter Second Quarter Third Quarter Fourth Quarter Total Collaboration revenue $ — $ — $ — $ — $ — Total operating expenses 14,869 18,955 20,836 24,588 79,248 Loss from operations (14,869 ) (18,955 ) (20,836 ) (24,588 ) (79,248 ) Net loss (13,954 ) (17,933 ) (18,465 ) (16,091 ) (66,443 ) Net loss per share applicable to common stockholders—basic and diluted $ (1.86 ) $ (2.36 ) $ (2.40 ) $ (2.04 ) $ (8.66 ) Due to a clerical error in the computation of the net loss attributable to common stockholders, the Company reported the net loss per share applicable to common stockholders—basic and diluted for the three months ended June 30, 2018 and 2017 as $2.94 and $2.31, respectively, in the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2018. The net loss per share applicable to common stockholders—basic and diluted for the second quarters ended June 30, 2018 and 2017 is $3.04 and $2.36, respectively, as shown in the chart above. The Company concluded that this error was not material to the periods impacted. During the three months ended December 31, 2018, the fair value of contingent consideration decreased by $14.6 million as a result of an increase in the discount rate (see Note 5). |
Summary of Significant Accoun_2
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Use of Estimates | Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual for research and development expenses, the revenue recognized from collaboration agreements, the valuation of common stock and stock-based awards, the valuation of assets acquired and liabilities assumed in business combinations, and the impairment of identifiable intangible assets and goodwill. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. |
Cash and Cash Equivalents | Cash and Cash Equivalents All highly liquid investments purchased with an original maturity date of three months or less at the date of purchase are considered to be cash equivalents. Cash equivalents consisted of money market funds as of December 31, 2018 and 2017. |
Investments | Investments The Company’s debt security investments are classified as available-for-sale and are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity (deficit). Realized gains and losses and declines in value determined to be other than temporary are based on the specific identification method and are included as a component of other income (expense), net in the consolidated statements of operations. The Company evaluates its investments with unrealized losses for other-than-temporary impairment. When assessing investments for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary,” the Company reduces the investment to fair value through a charge to the statement of operations. No such adjustments were necessary during the periods presented. The Company’s investments as of December 31, 2018 and 2017 had original maturities of less than one year. |
Concentrations of Credit Risk | Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents as well as short-term investments. Cash, cash equivalents and short-term investments consist of demand deposits, money market funds and U.S. government agency bonds. The Company generally maintains balances in various operating accounts with financial institutions that management believes to be of high credit quality, in amounts that may exceed federally insured limits. The Company has not experienced any losses related to its cash, cash equivalents and short-term investments and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. |
Restricted Cash | Restricted Cash In connection with its operating lease commitments, the Company issued letters of credit collateralized by cash deposits that are classified as restricted cash in the consolidated balance sheets. Restricted cash amounts have been classified as current assets based on the release dates of the restrictions under the letters of credit, which occur annually. |
Deferred Offering Costs | Deferred Offering Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of proceeds generated as a result of the offering. Should an in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations. As of December 31, 2018, the Company had no deferred offering costs. As of December 31, 2017, the Company recorded deferred offering costs of $0.5 million in connection with its IPO. |
Property and Equipment | Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful lives of each asset. Estimated useful lives are periodically assessed to determine if changes are appropriate. Upon retirement or sale, the related cost and accumulated depreciation and amortization are removed from the accounts and any resulting gain or loss is included in the consolidated statements of operations. Repair and maintenance costs are expensed as incurred. The estimated useful lives of the Company’s property and equipment are as follows: Estimated Useful Life Laboratory equipment 5 years Computer equipment 3 years Office equipment 5 years Leasehold improvements Shorter of lease term or 10 years Costs for capital assets not yet placed into service are capitalized as construction-in-progress and depreciated or amortized in accordance with the above useful lives once placed into service. Property and equipment are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate an asset group for recoverability, the Company compares the forecasted undiscounted cash flows expected to result from the use and eventual disposition of the asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use and eventual disposition of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows using market participant assumptions. The Company did not record any impairment losses on property and equipment during the years ended December 31, 2018 and 2017. |
Revenue Recognition | Revenue Recognition The terms of the Company’s collaboration agreements may include consideration such as non-refundable license fees, funding of research and development services, payments due upon the achievement of clinical and pre-clinical performance-based development milestones, regulatory milestones, manufacturing services, sales-based milestones and royalties on product sales. The Company had no revenue prior to the Sanofi Agreement, therefore the adoption of Financial Accounting Standards Board (“FASB”) ASC 606, Revenue from Contracts with Customers The Company recognizes the transaction price allocated to upfront license payments as revenue upon delivery of the license to the customer and resulting ability of the customer to use and benefit from the license, if the license is determined to be distinct from the other performance obligations identified in the contract. If the license is considered to not be distinct from other performance obligations, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied (i) at a point in time, but only for licenses determined to be distinct from other performance obligations in the contract, or (ii) over time, and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from license payments. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Sanofi Agreement entitles the Company to additional payments upon the achievement of performance-based milestones. These milestones are generally categorized into three types: development milestones, generally based on the advancement of the Company’s pipeline and initiation of clinical trials; regulatory milestones, generally based on the submission, filing or approval of regulatory applications such as a new drug application (“NDA”) in the United States; and sales-based milestones, generally based on meeting specific thresholds of sales in certain geographic areas. The Company is also eligible to receive from Sanofi tiered royalty payments on worldwide net sales of mRNA vaccines. For each collaboration that includes development milestone payments, the Company evaluates whether it is probable that the consideration associated with each milestone will not be subject to a significant reversal in the cumulative amount of revenue recognized. Amounts that meet this threshold are included in the transaction price using the most likely amount method, whereas amounts that do not meet this threshold are considered constrained and excluded from the transaction price until they meet this threshold. Milestones tied to regulatory approval, and therefore not within the Company’s control, are considered constrained until such approval is received. Upfront and ongoing development milestones per its collaboration agreements are not subject to refund if the development activities are not successful. At the end of each subsequent reporting period, the Company re-evaluates the probability of a significant reversal of the cumulative revenue recognized for the milestones, and, if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues from collaborators in the period of adjustment. The Company agreement that includes . The Company considers the underlying facts and circumstances of these agreements, noting whether the future payments are contingent upon future sales and whether they are dependent on a third party’s ability to successfully commercialize a product using the licensed intellectual property. The Company also considers whether the license is the only, or predominant, item to which the milestone payments and royalties relate. If the Company concludes the license is the predominant item in the agreement, therefore the primary driver of value, the ASC 606 requires the Company to allocate the arrangement consideration on a relative standalone selling price basis for each performance obligation after determining the transaction price of the contract and identifying the performance obligations to which that amount should be allocated. The relative standalone selling price is defined in ASC 606 as the price at which an entity would sell a promised good or service separately to a customer. If other observable transactions in which the Company has sold the same performance obligation separately are not available, the Company is required to estimate the standalone selling price of each performance obligation. Key assumptions to determine the standalone selling price may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. Whenever the Company determines that a contract should be accounted for as a combined performance obligation it will utilize the cost-to-cost input method. Revenue will be recognized over time using the cost-to-cost input method, based on the total estimated costs to fulfill the obligations. The Company will recognize revenue as services are delivered. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. The Company evaluates its collaborative agreements for proper classification in the consolidated statements of operations based on the nature of the underlying activity. Transactions between collaborators recorded in the Company’s consolidated statements of operations are recorded on either a gross or net basis, depending on the characteristics of the collaborative relationship. For revenue generating arrangements where the Company, as a vendor, provides consideration to a licensor or collaborator, as a customer, the Company applies the accounting standard that governs such transactions. This standard addresses the accounting for revenue arrangements where both the vendor and the customer make cash payments to each other for services and/or products. A payment to a customer is presumed to be a reduction of the transaction price unless the Company receives an identifiable benefit for the payment and it can reasonably estimate the fair value of the benefit received. Payments to a customer that are deemed a reduction of the transaction price are recorded first as a reduction of revenue, to the extent of both cumulative revenue recorded to date and probable future revenues, which include any unamortized deferred revenue balances, under all arrangements with such customer, and then as an expense. Payments that are not deemed to be a reduction of the transaction price are recorded as an expense. Consideration that does not meet the requirements to satisfy the above revenue recognition criteria is a contract liability and is recorded as deferred revenue in the consolidated balance sheets. Although the Company follows detailed guidelines in measuring revenue, certain judgments affect the application of its revenue policy. For example, in connection with the Sanofi Agreement, the Company has recorded short-term and long-term deferred revenue on its consolidated balance sheets based on the Company’s best estimate of when such revenue will be recognized. Short-term deferred revenue consists of amounts that are expected to be recognized as revenue in the next 12 months. Amounts that the Company expects will not be recognized within the next 12 months are classified as long-term deferred revenue. The estimate of deferred revenue also reflects management’s estimate of the periods of the Company’s involvement in certain of its collaborations. The Company’s performance obligations under these collaborations consist of participation on steering committees and the performance of other research and development services. In certain instances, the timing of satisfying these obligations can be difficult to estimate. Accordingly, the Company’s estimates may change in the future. Such changes to estimates would result in a change in revenue recognition amounts. If these estimates and judgments change over the course of these agreements, it may affect the timing and amount of revenue that the Company will recognize and record in future periods. At December 31, 2018, the Company had short-term and long-term deferred revenue of $2.6 million and $41.8 million, respectively, related to the Sanofi Agreement. Under ASC 606, the Company will recognize revenue and record a receivable when it fulfills its performance obligations under the Sanofi Agreement. When no further performance obligation is required to be satisfied, the Company will recognize revenue for the portion satisfied and record a receivable. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. The Company expenses incremental costs of obtaining a contract as and when incurred if the expected amortization period of the asset that the Company would have recognized is one year or less or the amount is immaterial. At December 31, 2018, the Company has not capitalized any costs to obtain any of its contracts. |
Business Combinations | Business Combinations The Company accounts for business combinations using the acquisition method of accounting. Application of this method of accounting requires that (i) identifiable assets acquired (including identifiable intangible assets) and liabilities assumed generally be measured and recognized at fair value as of the acquisition date and (ii) the excess of the purchase price over the net fair value of identifiable assets acquired and liabilities assumed be recognized as goodwill, which is not amortized for accounting purposes but is subject to testing for impairment at least annually. Acquired in-process research and development (“IPR&D”) is recognized at fair value and initially characterized as an indefinite-lived intangible asset, irrespective of whether the acquired IPR&D has an alternative future use. Transaction costs related to business combinations are expensed as incurred. Determining the fair value of assets acquired and liabilities assumed in a business combination requires management to use significant judgment and estimates, especially with respect to intangible assets. Critical estimates in valuing certain identifiable assets include, but are not limited to, the selection of valuation methodologies, estimates of future revenue and cash flows, expected long-term market growth, future expected operating expenses, costs of capital and appropriate discount rates. Management’s estimates of fair value are based upon assumptions believed to be reasonable, but which are inherently uncertain and, as a result, actual results may differ materially from estimates. During the measurement period, which extends no later than one year from the acquisition date, the Company may record certain adjustments to the carrying value of the assets acquired and liabilities assumed with the corresponding offset to goodwill. After the measurement period, all adjustments are recorded in the consolidated statements of operations as operating expenses or income. Acquisition-related contingent consideration, which consists of potential milestone and earnout payment obligations as well as anti-dilution rights provided to Shire (see Note 3), was recorded in the consolidated balance sheets at its acquisition-date estimated fair value, in accordance with the acquisition method of accounting. The fair value of the acquisition-related contingent consideration is remeasured each reporting period, with changes in fair value recorded in the consolidated statements of operations. The fair value measurement is based on significant inputs not observable by market participants and thus represents a Level 3 input in the fair value hierarchy (see Note 4). |
Asset Acquisitions | Asset Acquisitions The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire IPR&D with no alternative future use is charged to expense at the acquisition date. |
In-Process Research and Development | In-Process Research and Development The fair value of IPR&D acquired through a business combination is capitalized as an indefinite- and definite-lived intangible asset until the completion or abandonment of the related research and development activities. When the related research and development is completed or a change in circumstance occurs that defines the useful life, the asset is reclassified to a definite-lived asset and amortized over its estimated useful life. When a change between these classes occurs, the Company will perform an impairment test. The fair value of an IPR&D intangible asset is typically determined using an income approach whereby management forecasts the net cash flows expected to be generated by the asset over its estimated useful life. The net cash flows reflect the asset’s stage of completion, the probability of technical success, the projected costs to complete, expected market competition, and an assessment of the asset’s life-cycle. The net cash flows are then adjusted to present value by applying an appropriate discount rate that reflects the risk factors associated with the cash flow streams. Indefinite-lived IPR&D is not subject to amortization, but is tested annually for impairment or more frequently if there are indicators of impairment. The Company tests its indefinite-lived IPR&D annually for impairment on October 1st. In testing indefinite-lived IPR&D for impairment, the Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances would indicate that it is more likely than not that its fair value is less than its carrying amount, or the Company can perform a quantitative impairment analysis to determine the fair value of the indefinite-lived IPR&D without performing a qualitative assessment. Qualitative factors that the Company considers include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If the Company chooses to first assess qualitative factors and the Company determines that it is more likely than not that the fair value of the indefinite-lived IPR&D is less than its carrying amount, the Company would then determine the fair value of the indefinite-lived IPR&D. Under either approach, if the fair value of the indefinite-lived IPR&D is less than its carrying amount, an impairment charge is recognized in the consolidated statements of operations. During the years ended December 31, 2018 and 2017, the Company did not recognize any impairment charges related to its definite-lived IPR&D (see Note 4). In December 2018, the Company submitted an IND to the FDA to support the initiation of a Phase 1/2 clinical trial for MRT5201 in patients with OTC deficiency. In January 2019, the FDA notified the Company that its IND for MRT5201 was placed on clinical hold. The Company determined this clinical hold was an indicator of impairment and as a result, retested the indefinite-lived IPR&D related to the OTC program for impairment. The Company performed a quantitative impairment analysis whereby the Company forecasted the net cash flows expected to be generated by the indefinite-lived IPR&D related to the OTC program over its estimated useful life. The net cash flows reflected the program’s stage of completion, the probability of technical success, the projected costs to complete, expected market competition and an assessment of the program’s life-cycle. The net cash flows were then adjusted to present value by applying an appropriate discount rate that reflects the risk factors associated with the cash flow streams. Following this retest the Company determined the indefinite-lived IPR&D related to the OTC program was not impaired. Therefore, the Company did not recognize an impairment charge. Definite-lived IPR&D is recorded at fair value and amortized over the greater of economic consumption or on a straight-line basis over its estimated useful life. Definite-lived IPR&D is tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. If an impairment review is performed to evaluate an asset group for recoverability, the Company compares the forecasted undiscounted cash flows expected to result from the use and eventual disposition of the asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use and eventual disposition of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows using market participant assumptions. |
Goodwill | Goodwill Goodwill represents the excess of the fair value of the consideration transferred over the fair value of the net tangible and identifiable intangible assets acquired in a business combination. Goodwill is not subject to amortization, but is tested annually for impairment or more frequently if there are indicators of impairment. The Company tests its goodwill annually for impairment on October 1st. The Company has determined that there is a single reporting unit for purposes of testing goodwill for impairment. In testing goodwill for impairment, the Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances would indicate that it is more likely than not that the fair value of the reporting unit was less than its carrying amount, or the Company can perform a two-step quantitative impairment analysis without performing a qualitative assessment. Examples of such events or circumstances considered in the Company’s qualitative assessment include, but are not limited to, a significant adverse change in legal or business climate, an adverse regulatory action or unanticipated competition. If the Company chooses to first assess qualitative factors and the Company determines that it is more likely than not that the fair value of its reporting unit is less than its carrying amount, the Company would then perform a two-step quantitative impairment test. The two-step test starts with comparing the fair value of the reporting unit to the carrying amount of a reporting unit, including goodwill. If the fair value of the reporting unit exceeds the carrying amount, no impairment loss is recognized. However, if the fair value of the reporting unit is less than its carrying value, the second step of the impairment test is performed to determine if goodwill is impaired. If the Company determines that goodwill is impaired, the carrying value of the goodwill is written down to its fair value and an impairment charge is recognized in the consolidated statements of operations. During the years ended December 31, 2018 and 2017, the Company did not recognize any impairment charges related to goodwill. |
Fair Value Measurements | Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and short-term investments are carried at fair value, determined based on Level 2 inputs in the fair value hierarchy described above (see Note 5). The Company’s contingent consideration liability is carried at fair value, determined based on Level 3 inputs in the fair value hierarchy described above (see Note 5). The carrying values of the Company’s prepaid expenses and other current assets, accounts payable, accrued expenses and other short-term liabilities approximate their fair values due to the short-term nature of these assets and liabilities. |
Segment Information | Segment Information The Company manages its operations as a single operating segment for the purposes of assessing performance and making operating decisions. The Company’s primary focus is on the advancement of the Company’s MRT platform to treat diseases caused by protein or gene dysfunction. |
Research and Development Costs | Research and Development Costs Costs associated with internal research and development and external research and development services, including drug development and preclinical studies, are expensed as incurred. Research and development expenses include costs for salaries, employee benefits, subcontractors, facility-related expenses, depreciation and amortization, including amortization related to definite-lived IPR&D intangible assets, stock-based compensation, third-party license fees, laboratory supplies, and external costs of outside vendors engaged to conduct discovery, preclinical and clinical development activities and clinical trials as well as to manufacture clinical trial materials, and other costs. The Company recognizes external research and development costs based on an evaluation of the progress to completion of specific tasks using information provided to the Company by its service providers. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. Such prepaid expenses are recognized as an expense when the services have been performed or the goods have been delivered, or when it is no longer expected that the goods will be delivered or the services rendered. Upfront payments, milestone payments (other than those deemed contingent consideration in a business combination) and annual maintenance fees under license agreements are expensed in the period in which they are incurred. |
Research and Development Contract Costs and Accruals | Research and Development Contract Costs and Accruals The Company has entered into various research and development-related contracts with companies both inside and outside of the United States. The related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ materially from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs. |
Patent Costs | Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses. |
Stock-Based Compensation | Stock-Based Compensation The Company measures all stock-based awards granted to employees and directors based on their fair value on the date of the grant and recognizes compensation expense for those awards over the requisite service period, which is generally the vesting period of the respective award. For stock-based awards with service-based vesting conditions, the Company recognizes compensation expense using the straight-line method. For stock-based awards with both performance-based and service-based vesting conditions, the Company recognizes compensation expense using the graded-vesting method over the requisite service period, commencing when achievement of the performance condition becomes probable. The Company recognizes adjustments to compensation expense for forfeitures as they occur. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model, which requires inputs based on certain subjective assumptions, including the expected stock price volatility, the expected term of the option, the risk-free interest rate for a period that approximates the expected term of the option, and the Company’s expected dividend yield (see Note 11). The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date. Through December 31, 2018, for stock-based awards granted to non-employee consultants, compensation expense is recognized over the period during which services are rendered by such non-employee consultants until completed. At the end of each financial reporting period prior to completion of the service, the fair value of these awards is remeasured using the then-current fair value of the Company’s common stock and updated assumption inputs in the Black-Scholes option-pricing model. The Company classifies stock-based compensation expense in its consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. |
Classification and Accretion of Redeemable Convertible Preferred Stock | Classification and Accretion of Redeemable Convertible Preferred Stock The Company has classified its redeemable convertible preferred stock outside of stockholders’ equity (deficit) because the shares contain certain redemption features that are not solely within the control of the Company. Costs incurred in connection with the issuance of each series of redeemable convertible preferred stock are recorded as a reduction of gross proceeds from issuance. The carrying values of redeemable convertible preferred stock are accreted to their redemption values through a charge to additional paid-in capital or accumulated deficit over the period from date of issuance to the earliest date on which the holders could, at their option, elect to redeem their shares. Upon the closing of the Company’s IPO in July 2018, all then-outstanding shares of Redeemable Convertible Preferred Stock converted into shares of common stock according to their terms. As of December 31, 2018 there were no shares of Redeemable Convertible Preferred Stock authorized, issued or outstanding. |
Comprehensive Loss | Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) was unrealized gains (losses) on U.S. government agency bonds, which are classified as available-for-sale-securities. |
Income Taxes | Income Taxes The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the consolidated financial statements or in the Company’s tax returns. Deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the consolidated financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. |
Net Income (Loss) per Share | Net Income (Loss) per Share The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) attributable to common stockholders is computed by adjusting net income (loss) attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period, including potential dilutive shares of common stock. For purposes of this calculation, outstanding stock options, unvested restricted common stock and redeemable convertible preferred stock are considered potential dilutive shares of common stock. The Company’s preferred stock contractually entitles the holders of such shares to participate in dividends but does not contractually require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss attributable to common stockholders, such losses are not allocated to such participating securities. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive shares of common stock are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common stockholders for the years ended December 31, 2018 and 2017. |
Recently Adopted Accounting Pronouncement | Recently Adopted Accounting Pronouncements In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments (Topic 230) In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230) In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation: Scope of Modification Accounting (Topic 718) |
Recently Issued Accounting Pronouncements | Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02 , Leases (Topic 842) In July 2018, the FASB subsequently issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements (“ASU 2018-11”), which includes certain amendments to ASU 2016-02 intended to provide relief in implementing the new standard. Among these amendments is the option to not restate comparative periods presented in the financial statements. The Company has elected this transition approach, using a cumulative-effect adjustment on the effective date of the standard, with comparative periods presented in accordance with the existing guidance in ASC 840. The Company adopted the standard on January 1, 2019 and has used the effective date as its date of initial application. The Company expects to take advantage of certain available expedients by electing the transition package of practical expedients permitted within ASU 2016-02, which allows the Company to not reassess previous accounting conclusions around whether arrangements are, or contain, leases, the classification of leases, and the treatment of initial direct costs. The Company also has made an accounting policy election to exclude leases with an initial term of twelve months or less from the balance sheet. The Company is still assessing the impact of adopting the new standard, and currently expects a material impact to its consolidated balance sheet in recognizing additional lease liabilities and right-of-use assets as of January 1, 2019 related to its operating leases. The Company further expects to provide enhanced new disclosures about its leasing arrangements in its financial statements for future periods. The Company does not expect that the new standard will have a material impact on the Company’s consolidated statement of operations or cash flows. In June 2016, the FASB issued guidance on the Measurement of Credit Losses on Financial Instruments. The guidance requires that credit losses be reported using an expected losses model rather than the incurred losses model that is currently used, and establishes additional disclosures related to credit risks. For available-for-sale debt securities with unrealized losses, the standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. This standard will be effective for the Company on January 1, 2020. The Company is currently evaluating the potential impact that this standard may have on the Company’s consolidated financial statements and related disclosures. In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Other: Simplifying the Test for Goodwill Impairment (Topic 350) The Company does not expect that the adoption of this new standard will have a material impact on its consolidated financial statements and related disclosures. In June 2018, the FASB issued ASU No. 2018-07, Compensation-Stock Compensation (Topic 718) The Company does not expect that the adoption of this new standard will have a material impact on its consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808) Revenue Recognition Collaborative Arrangements |
Summary of Significant Accoun_3
Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Estimated Useful Lives of Property and Equipment | The estimated useful lives of the Company’s property and equipment are as follows: Estimated Useful Life Laboratory equipment 5 years Computer equipment 3 years Office equipment 5 years Leasehold improvements Shorter of lease term or 10 years |
Collaboration Agreement (Tables
Collaboration Agreement (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Summary of Net Revenues From Collaboration | The following table summarizes the Company’s net revenues from collaboration (in thousands): Year Ended December 31, 2018 2017 Collaboration revenue $ 1,420 $ — |
Balance of Contract Liabilities Related to Collaboration Agreements | The following table presents the balance of the Company’s contract liabilities (in thousands): December 31, 2018 2017 Contract liabilities Deferred revenues $ 44,413 $ — |
Acquisitions, Goodwill and Ot_2
Acquisitions, Goodwill and Other Intangible Assets (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Acquisitions Goodwill And Other Intangible Assets [Abstract] | |
Summary of Fair Value of Consideration Transferred | The aggregate acquisition-date fair value of consideration transferred was determined to be $112.2 million, consisting of the following (in thousands): Fair value of common stock $ 41,089 Fair value of contingent consideration — potential milestone and earnout payments 62,666 Fair value of contingent consideration — anti-dilution rights 8,407 Total fair value of purchase consideration $ 112,162 |
Summary of Fair Value of Consideration Allocated to Tangible and Intangible Assets Acquired | The total consideration transferred was allocated to the tangible and identifiable intangible assets acquired based on their estimated fair values as follows (in thousands): Identifiable intangible assets $ 106,907 Property and equipment 2,416 Deferred tax assets 1,308 Deferred tax liabilities (18,520 ) Valuation allowance for deferred tax assets (1,308 ) Goodwill 21,359 Total purchase price consideration $ 112,162 |
Fair Values of Identifiable Intangible Assets as of Acquisition Date | The fair values of the identifiable intangible assets as of the acquisition date were as follows (in thousands): In-process research and development — MRT $ 45,992 In-process research and development — CF 42,291 In-process research and development — OTC 18,559 Lease agreement 65 Total identifiable intangible assets $ 106,907 |
Fair Value of Financial Asset_2
Fair Value of Financial Assets and Liabilities (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Fair Value Disclosures [Abstract] | |
Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis | The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands): Fair Value Measurements as of December 31, 2018 Using: Level 1 Level 2 Level 3 Total Assets: Money market funds $ — $ 23,318 $ — $ 23,318 U.S. government agency bonds — 88,904 — 88,904 $ — $ 112,222 $ — $ 112,222 Liabilities: Contingent consideration $ — $ — $ 103,642 $ 103,642 $ — $ — $ 103,642 $ 103,642 Fair Value Measurements as of December 31, 2017 Using: Level 1 Level 2 Level 3 Total Assets: Money market funds $ — $ 28,636 $ — $ 28,636 U.S. government agency bonds — 9,997 — 9,997 $ — $ 38,633 $ — $ 38,633 Liabilities: Contingent consideration $ — $ — $ 81,009 $ 81,009 $ — $ — $ 81,009 $ 81,009 |
Schedule of Unobservable Inputs and Fair Value Components of Contingent Consideration | The following tables presents the unobservable inputs and fair value of the components of the contingent consideration (dollar amounts in thousands): Unobservable Inputs at December 31, 2018 and 2017 Fair Value at Projected Year December 31, Discount Rate of Payment 2018 2017 Earnout payments 14.5% - 15.0% 2025 - 2039 $ 94,999 $ 72,896 Milestone payments 14.5% - 15.0% 2025 - 2030 8,643 6,817 Anti-dilution rights 1.39% - 1.64% N/A — 1,296 $ 103,642 $ 81,009 |
Schedule of Total Acquisition Related Contingent Consideration Liability | The following table presents a roll-forward of the total acquisition-related contingent consideration liability (in thousands): Fair Value Balance as of December 31, 2017 $ 81,009 Change in fair value of contingent consideration 25,020 Issuance of common stock in full settlement of contingent consideration anti-dilution liability (2,387 ) Balance as of December 31, 2018 $ 103,642 |
Property and Equipment, Net (Ta
Property and Equipment, Net (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Property Plant And Equipment [Abstract] | |
Schedule of Property and Equipment, Net | Property and equipment, net consisted of the following (in thousands): December 31, 2018 2017 Laboratory equipment $ 7,012 $ 5,382 Computer equipment 686 481 Office equipment 836 249 Leasehold improvements 5,635 1,131 Construction in progress 959 2,591 15,128 9,834 Less: Accumulated depreciation and amortization (4,883 ) (3,056 ) $ 10,245 $ 6,778 |
Accrued Expenses (Tables)
Accrued Expenses (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Payables And Accruals [Abstract] | |
Schedule of Accrued Expenses | Accrued expenses consisted of the following (in thousands): December 31, 2018 2017 Accrued employee compensation and benefits $ 2,933 $ 2,252 Accrued external research and development expenses 1,901 1,115 Accrued consultant and professional fees 977 1,130 Other 736 1,391 $ 6,547 $ 5,888 |
Redeemable Convertible Prefer_2
Redeemable Convertible Preferred Stock (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Temporary Equity Disclosure [Abstract] | |
Schedule of Redeemable Convertible Preferred Stock | As of December 31, 2017, Redeemable Convertible Preferred Stock consisted of the following (in thousands, except share amounts): December 31, 2017 Preferred Shares Authorized Preferred Shares Issued and Outstanding Carrying Value Liquidation Preference Common Stock Issuable Upon Conversion Series A preferred stock 36,194,026 36,194,026 $ 36,194 $ 36,194 6,514,986 Series B preferred stock 59,133,987 59,133,987 64,002 63,199 10,644,210 Series C preferred stock 50,505,051 46,960,279 92,700 92,981 8,452,913 145,833,064 142,288,292 $ 192,896 $ 192,374 25,612,109 |
Incentive Stock Options and R_2
Incentive Stock Options and Restricted Stock (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Summary of Stock Option Activity | The following table summarizes the Company’s stock option activity since December 31, 2017 (in thousands, except share and per share amounts): Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Intrinsic Value (in years) Outstanding as of December 31, 2017 4,364,916 $ 7.17 9.79 $ 977 Granted 2,169,290 $ 8.82 Exercised (49,459 ) $ 5.62 Forfeited (248,741 ) $ 6.62 Outstanding as of December 31, 2018 6,236,006 $ 7.78 8.74 $ 1,104 Vested as of December 31, 2018 1,827,004 $ 7.16 7.95 $ 632 Vested and expected to vest as of December 31, 2018 6,236,006 $ 7.78 8.74 $ 1,104 Vested as of December 31, 2017 661,593 $ 7.04 9.72 $ 231 Vested and expected to vest as of December 31, 2017 4,364,916 $ 7.17 9.79 $ 977 |
Summary of Restricted Stock Activity | The following table summarizes the Company’s restricted stock activity since December 31, 2017: Number of Shares Weighted Average Grant-Date Fair Value Unvested restricted common stock outstanding as of December 31, 2017 526,478 $ 1.14 Forfeited restricted common stock (2,446 ) $ 1.28 Vested restricted common stock (304,884 ) $ 1.04 Unvested restricted common stock outstanding as of December 31, 2018 219,148 $ 1.27 |
Summary of Stock-Based Compensation Expense | Stock-based compensation expense was classified in the consolidated statements of operations as follows (in thousands): Year Ended December 31, 2018 2017 Research and development expenses $ 3,756 $ 1,886 General and administrative expenses 3,577 1,794 $ 7,333 $ 3,680 |
Employee and Board of Directors [Member] | |
Summary of Assumptions Used in Black-Scholes Option-Pricing Model to Determine Grant-Date Fair Value of Stock Option Granted | The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted to employees and directors: Year Ended December 31, 2018 2017 Risk-free interest rate 2.81 % 2.15 % Expected term (in years) 6.0 6.0 Expected volatility 75.5 % 59.0 % Expected dividend yield 0 % 0 % |
Non Employee [Member] | |
Summary of Assumptions Used in Black-Scholes Option-Pricing Model to Determine Grant-Date Fair Value of Stock Option Granted | The following table presents the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted to a non-employee: Year Ended December 31, 2017 Risk-free interest rate 2.08 % Expected term (in years) 10.0 Expected volatility 60.9 % Expected dividend yield 0 % |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Income Tax Disclosure [Abstract] | |
Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate and Effective Income Tax Rate | A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2018 2017 U.S. federal statutory income tax rate (21.0 )% (34.0 )% State income taxes, net of federal benefit (6.9 ) (5.4 ) Research and development tax credits and orphan drug credit (5.5 ) (4.2 ) Stock-based compensation 0.5 1.5 Other permanent differences 0.3 0.4 Remeasurement of deferred taxes due to the Tax Act — 15.9 Change in deferred tax asset valuation allowance 27.7 10.0 Other (0.4 ) — Effective income tax rate (5.3 )% (15.8 )% |
Schedule of Components of Deferred Tax Assets and Liabilities | Components of the Company’s deferred tax assets and liabilities were as follows (in thousands): December 31, 2018 2017 Deferred tax assets: Net operating loss carryforwards $ 50,917 $ 32,524 Research and development tax credit and orphan drug credit carryforwards 13,581 6,372 Depreciation and amortization 2,380 2,025 Accrued expenses and other 2,894 1,090 Total deferred tax assets 69,772 42,011 Deferred tax liabilities: Indefinite-lived intangible assets (2,109 ) (8,445 ) Total deferred tax liabilities (2,109 ) (8,445 ) Valuation allowance (68,143 ) (39,605 ) Net deferred tax liabilities $ (480 ) $ (6,039 ) |
Summary of Changes in Valuation Allowance for Deferred Tax Assets | Changes in the valuation allowance for deferred tax assets during the years ended December 31, 2018 and 2017 related primarily to the increase in net operating loss carryforwards and research and development tax credit carryforwards in 2018 and 2017, and the impact of the Tax Act in 2017, and were as follows (in thousands): Year Ended December 31, 2018 2017 Valuation allowance at beginning of year $ (39,605 ) $ (31,729 ) Decreases recorded as benefit to income tax provision — 18,628 Increases recorded to income tax provision (28,538 ) (26,504 ) Valuation allowance at end of year $ (68,143 ) $ (39,605 ) |
Net Loss per Share (Tables)
Net Loss per Share (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Earnings Per Share [Abstract] | |
Summary of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders | Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): Year Ended December 31, 2018 2017 Numerator: Net loss $ (97,395 ) $ (66,443 ) Accretion of redeemable convertible preferred stock to redemption value (644 ) (719 ) Net loss attributable to common stockholders $ (98,039 ) $ (67,162 ) Denominator: Weighted average common shares outstanding—basic and diluted 26,945,508 7,756,180 Net loss per share attributable to common stockholders—basic and diluted $ (3.64 ) $ (8.66 ) |
Schedule of Potential Securities Excluded from Computation of Earnings Per Share | The Company excluded the following potential shares of common stock, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Year Ended December 31, 2018 2017 Options to purchase common stock 6,236,006 4,364,916 Unvested restricted common stock 219,148 526,478 Redeemable convertible preferred stock (as converted to common stock) — 25,612,109 6,455,154 30,503,503 |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Commitments And Contingencies Disclosure [Abstract] | |
Schedule of Future Minimum Lease Payments Due Under Operating Leases | The following table summarizes the future minimum lease payments due under the Company’s operating leases as of December 31, 2018 (in thousands): Year Ending December 31, 2019 $ 2,534 2020 2,610 2021 2,688 2022 2,769 2023 2,852 2024 and thereafter 13,096 $ 26,549 |
Costs Associated with Restruc_2
Costs Associated with Restructuring (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Restructuring And Related Activities [Abstract] | |
Summary of Changes in Accrued Restructuring Costs | Changes in accrued restructuring costs were as follows (in thousands): Balance at December 31, 2016 $ — Charges 473 Payments (473 ) Balance at December 31, 2017 $ — |
Selected Quarterly Financial _2
Selected Quarterly Financial Information (Unaudited) (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Selected Quarterly Financial Information [Abstract] | |
Schedule of Selected Quarterly Financial Information | The following table contains quarterly financial information for 2018 and 2017 (in thousands, except per share amounts). The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Total Collaboration revenue $ — $ — $ 238 $ 1,182 $ 1,420 Total operating expenses 22,389 29,062 45,719 8,480 105,650 Loss from operations (22,389 ) (29,062 ) (45,481 ) (7,298 ) (104,230 ) Net loss (21,209 ) (27,503 ) (42,646 ) (6,037 ) (97,395 ) Net loss per share applicable to common stockholders—basic and diluted $ (2.35 ) $ (3.04 ) $ (0.97 ) $ (0.13 ) $ (3.64 ) 2017 First Quarter Second Quarter Third Quarter Fourth Quarter Total Collaboration revenue $ — $ — $ — $ — $ — Total operating expenses 14,869 18,955 20,836 24,588 79,248 Loss from operations (14,869 ) (18,955 ) (20,836 ) (24,588 ) (79,248 ) Net loss (13,954 ) (17,933 ) (18,465 ) (16,091 ) (66,443 ) Net loss per share applicable to common stockholders—basic and diluted $ (1.86 ) $ (2.36 ) $ (2.40 ) $ (2.04 ) $ (8.66 ) |
Nature of the Business and Ba_2
Nature of the Business and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands | Jul. 24, 2018USD ($)$ / sharesshares | Jul. 02, 2018$ / sharesshares | Jun. 15, 2018 | Dec. 31, 2018USD ($) | Sep. 30, 2018USD ($) | Jun. 30, 2018USD ($) | Mar. 31, 2018USD ($) | Dec. 31, 2017USD ($) | Sep. 30, 2017USD ($) | Jun. 30, 2017USD ($) | Mar. 31, 2017USD ($) | Dec. 31, 2018USD ($) | Dec. 31, 2017USD ($) | Jun. 08, 2018USD ($)Disease |
Initial Public Offering [Line Items] | ||||||||||||||
Reverse stock split description | one-for-5.5555 reverse stock split | |||||||||||||
Reverse stock split ratio | 0.1800 | |||||||||||||
Net loss | $ (6,037) | $ (42,646) | $ (27,503) | $ (21,209) | $ (16,091) | $ (18,465) | $ (17,933) | $ (13,954) | $ (97,395) | $ (66,443) | ||||
Accumulated deficit | (246,203) | $ (148,808) | (246,203) | $ (148,808) | ||||||||||
Cash, cash equivalents, and short-term investments | $ 144,100 | $ 144,100 | ||||||||||||
Sanofi Pasteur Collaboration and Licensing Agreement [Member] | Sanofi Pasteur Inc [Member] | ||||||||||||||
Initial Public Offering [Line Items] | ||||||||||||||
Number of infectious disease pathogens | Disease | 5 | |||||||||||||
Period of research term | 3 years | |||||||||||||
Upfront payment received | $ 45,000 | |||||||||||||
Sanofi Pasteur Collaboration and Licensing Agreement [Member] | Sanofi Pasteur Inc [Member] | Maximum [Member] | ||||||||||||||
Initial Public Offering [Line Items] | ||||||||||||||
Extended period of research term | 8 years | |||||||||||||
Receivable from collaboration | $ 805,000 | |||||||||||||
IPO [Member] | ||||||||||||||
Initial Public Offering [Line Items] | ||||||||||||||
Issuance of common incentive units | shares | 364,371 | 9,350,000 | ||||||||||||
Common stock issued and sold, per share | $ / shares | $ 13 | $ 13 | ||||||||||||
Net proceeds from IPO | $ 113,200 | |||||||||||||
Underwriting discounts and commissions | 8,800 | |||||||||||||
Offering expenses | $ 4,300 | |||||||||||||
Shares of redeemable convertible preferred stock converted | shares | 142,288,292 | |||||||||||||
Shares of common stock issued upon conversion of redeemable convertible preferred stock | shares | 25,612,109 |
Summary of Significant Accoun_4
Summary of Significant Accounting Policies - Additional Information (Detail) | Jun. 07, 2018USD ($) | Dec. 31, 2018USD ($)shares | Sep. 30, 2018USD ($) | Dec. 31, 2018USD ($)Segmentshares | Dec. 31, 2017USD ($)shares |
Indefinite-lived Intangible Assets [Line Items] | |||||
Deferred offering costs | $ 0 | $ 0 | $ 500,000 | ||
Revenue | 1,182,000 | $ 238,000 | 1,420,000 | ||
Current portion of deferred revenue | 2,572,000 | 2,572,000 | |||
Deferred revenue, net of current portion | $ 41,841,000 | 41,841,000 | |||
Goodwill impairment charge | $ 0 | $ 0 | |||
Number of operating segment | Segment | 1 | ||||
Redeemable convertible preferred stock, shares authorized | shares | 0 | 0 | 145,833,064 | ||
Redeemable convertible preferred stock, shares Issued | shares | 0 | 0 | 142,288,292 | ||
Redeemable convertible preferred stock, shares outstanding | shares | 0 | 0 | 142,288,292 | ||
ASU 2016-18 [Member] | |||||
Indefinite-lived Intangible Assets [Line Items] | |||||
Increase in cash and cash equivalents as effect of adoption | $ 2,000,000 | ||||
In-Process Research and Development [Member] | |||||
Indefinite-lived Intangible Assets [Line Items] | |||||
Impairment charges on assets | 0 | $ 0 | |||
Sanofi Pasteur Collaboration and Licensing Agreement [Member] | |||||
Indefinite-lived Intangible Assets [Line Items] | |||||
Revenue | $ 0 | ||||
Current portion of deferred revenue | $ 2,600,000 | 2,600,000 | |||
Deferred revenue, net of current portion | $ 41,800,000 | 41,800,000 | |||
Property and Equipment [Member] | |||||
Indefinite-lived Intangible Assets [Line Items] | |||||
Impairment charges on assets | $ 0 | $ 0 |
Summary of Significant Accoun_5
Summary of Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Detail) | 12 Months Ended |
Dec. 31, 2018 | |
Laboratory Equipment [Member] | |
Property Plant And Equipment Estimated Useful Lives [Line Items] | |
Property plant and equipment useful life | 5 years |
Computer Equipment [Member] | |
Property Plant And Equipment Estimated Useful Lives [Line Items] | |
Property plant and equipment useful life | 3 years |
Office Equipment [Member] | |
Property Plant And Equipment Estimated Useful Lives [Line Items] | |
Property plant and equipment useful life | 5 years |
Leasehold Improvements [Member] | |
Property Plant And Equipment Estimated Useful Lives [Line Items] | |
Property plant and equipment estimated useful life | Shorter of lease term or 10 years |
Collaboration Agreement - Addit
Collaboration Agreement - Additional Information (Detail) - Sanofi Agreement [Member] $ in Millions | Jun. 08, 2018USD ($)Disease | Dec. 31, 2018USD ($) | Jul. 18, 2018USD ($) |
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] | |||
Number of infectious disease pathogens for vaccine development | Disease | 5 | ||
Period of research term | 3 years | ||
Upfront payment received | $ 45 | $ 45 | |
Additional fee per added pathogen option | 5 | ||
Maximum development and regulatory milestone payment receivable | 63 | ||
Technology and process transfer milestone payment receivable | $ 10 | ||
Royalty payment term | 10 years | ||
Collaborative agreement transaction price | $ 161.1 | ||
Non-refundable upfront payment | 45 | ||
Estimated reimbursable employee cost | 32.6 | ||
Estimated reimbursable development cost | 54.5 | ||
Estimated milestone payments | 19 | ||
Estimated for scaling up manufacturing capacity | $ 10 | ||
Reimbursable development costs payable period | 60 days | ||
Revenue recognizing period | 8 years | ||
Prepaids and Other Current Assets [Member] | |||
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] | |||
Accounts receivable | $ 0.8 | ||
Maximum [Member] | |||
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] | |||
Extended period of research term | 8 years | ||
Receivable from collaboration | $ 805 | ||
Sales milestone payment receivable | $ 85 |
Collaboration Agreement - Summa
Collaboration Agreement - Summary of Net Revenues From Collaboration (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended | |
Dec. 31, 2018 | Sep. 30, 2018 | Dec. 31, 2018 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |||
Collaboration revenue | $ 1,182 | $ 238 | $ 1,420 |
Collaboration Agreement - Balan
Collaboration Agreement - Balance of Contract Liabilities Related to Collaboration Agreements (Detail) $ in Thousands | Dec. 31, 2018USD ($) |
Contract liabilities | |
Deferred revenues | $ 44,413 |
Acquisitions, Goodwill and Ot_3
Acquisitions, Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) | Jul. 02, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Jun. 07, 2018 |
Business Acquisition [Line Items] | |||||
Milestone payments payable | $ 103,642,000 | $ 81,009,000 | |||
Goodwill | $ 21,359,000 | $ 21,359,000 | |||
Shire's MRT Program [Member] | |||||
Business Acquisition [Line Items] | |||||
Common stock issued as consideration | 5,815,560 | ||||
Milestone payments payable | $ 10,000,000 | $ 10,000,000 | |||
Obligation to consummate equity financing | $ 100,000,000 | ||||
Percentage of common stock to be issued under antidilution right on as converted | 18.00% | ||||
Percentage of common stock outstanding voting power | 19.90% | ||||
Common stock issued as consideration | 183,619 | ||||
Total fair value of purchase consideration | $ 112,200,000 | ||||
Business combination, consideration paid in shares | 5,815,560 | ||||
Fair value of common stock | $ 41,089,000 | ||||
Issuance of common stock in connection with acquisition of MRT program, Shares | 70,866 | ||||
Deferred tax liability | 18,520,000 | ||||
Deferred tax assets | 1,308,000 | ||||
Goodwill | $ 21,359,000 | ||||
Shire's MRT Program [Member] | Sanofi Agreement [Member] | |||||
Business Acquisition [Line Items] | |||||
Estimated useful life of intangible assets | 8 years | ||||
Amortization of Intangible Assets | $ 400,000 | ||||
Estimated amortization expense of intangible assets for 2019 | 3,200,000 | ||||
Estimated amortization expense of intangible assets for 2020 | 9,700,000 | ||||
Estimated amortization expense of intangible assets for 2021 | 10,500,000 | ||||
Estimated amortization expense of intangible assets for 2022 | 5,300,000 | ||||
Estimated amortization expense of intangible assets for 2023 | $ 2,000,000 | ||||
Shire's MRT Program [Member] | Lease Agreements [Member] | |||||
Business Acquisition [Line Items] | |||||
Estimated useful life of intangible assets | 1 year 6 months | ||||
Shire's MRT Program [Member] | General and Administrative Expenses [Member] | |||||
Business Acquisition [Line Items] | |||||
Acquisition-related costs | $ 3,000,000 | ||||
Shire's MRT Program [Member] | Bank Service Charges [Member] | Accrued Liabilities [Member] | |||||
Business Acquisition [Line Items] | |||||
Acquisition-related costs | $ 500,000 | ||||
Shire's MRT Program [Member] | Common Stock [Member] | |||||
Business Acquisition [Line Items] | |||||
Consideration transferred, fair value of common stock per share | $ 7.06 | ||||
Issuance of common stock in connection with acquisition of MRT program, Shares | 70,866 | ||||
Shire's MRT Program [Member] | Series C Redeemable Convertible Preferred Stock [Member] | |||||
Business Acquisition [Line Items] | |||||
Consideration transferred, fair value of common stock per share | $ 1.98 | ||||
Shire's MRT Program [Member] | Maximum [Member] | |||||
Business Acquisition [Line Items] | |||||
Milestone payments payable | $ 60,000,000 |
Acquisitions, Goodwill and Ot_4
Acquisitions, Goodwill and Other Intangible Assets - Summary of Fair Value of Consideration Transferred (Detail) - Shire's MRT Program [Member] $ in Thousands | 12 Months Ended |
Dec. 31, 2018USD ($) | |
Fair value of common stock | $ 41,089 |
Total fair value of purchase consideration | 112,162 |
Potential Milestone and Earnout Payments [Member] | |
Fair value of contingent consideration | 62,666 |
Anti- Dilution Rights [Member] | |
Fair value of contingent consideration | $ 8,407 |
Acquisitions, Goodwill and Ot_5
Acquisitions, Goodwill and Other Intangible Assets - Summary of Fair Value of Consideration Allocated to Tangible and Intangible Assets Acquired (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Business Acquisition [Line Items] | ||
Goodwill | $ 21,359 | $ 21,359 |
Shire's MRT Program [Member] | ||
Business Acquisition [Line Items] | ||
Identifiable intangible assets | 106,907 | |
Property and equipment | 2,416 | |
Deferred tax assets | 1,308 | |
Deferred tax liabilities | (18,520) | |
Valuation allowance for deferred tax assets | (1,308) | |
Goodwill | 21,359 | |
Total purchase price consideration | $ 112,162 |
Acquisitions, Goodwill and Ot_6
Acquisitions, Goodwill and Other Intangible Assets - Fair Values of Identifiable Intangible Assets as of Acquisition Date (Detail) - Shire's MRT Program [Member] $ in Thousands | Dec. 31, 2018USD ($) |
Business Acquisition [Line Items] | |
Total identifiable intangible assets | $ 106,907 |
Lease Agreements [Member] | |
Business Acquisition [Line Items] | |
Total identifiable intangible assets | 65 |
In-Process Research and Development [Member] | MRT Product [Member] | |
Business Acquisition [Line Items] | |
Total identifiable intangible assets | 45,992 |
In-Process Research and Development [Member] | Cystic Fibrosis [Member] | |
Business Acquisition [Line Items] | |
Total identifiable intangible assets | 42,291 |
In-Process Research and Development [Member] | OTC Deficiency [Member] | |
Business Acquisition [Line Items] | |
Total identifiable intangible assets | $ 18,559 |
Fair Value of Financial Asset_3
Fair Value of Financial Assets and Liabilities - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Assets: | ||
Total, assets | $ 112,222 | $ 38,633 |
Liabilities: | ||
Total, liabilities | 103,642 | 81,009 |
Fair Value, Inputs, Level 2 | ||
Assets: | ||
Total, assets | 112,222 | 38,633 |
Fair Value, Inputs, Level 3 | ||
Liabilities: | ||
Total, liabilities | 103,642 | 81,009 |
Money Market Funds | ||
Assets: | ||
Total, assets | 23,318 | 28,636 |
Money Market Funds | Fair Value, Inputs, Level 2 | ||
Assets: | ||
Total, assets | 23,318 | 28,636 |
U.S. Government Agency Bonds | ||
Assets: | ||
Total, assets | 88,904 | 9,997 |
U.S. Government Agency Bonds | Fair Value, Inputs, Level 2 | ||
Assets: | ||
Total, assets | 88,904 | 9,997 |
Contingent Consideration | ||
Liabilities: | ||
Total, liabilities | 103,642 | 81,009 |
Contingent Consideration | Fair Value, Inputs, Level 3 | ||
Liabilities: | ||
Total, liabilities | $ 103,642 | $ 81,009 |
Fair Value of Financial Asset_4
Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($) | Jul. 24, 2018 | Jul. 02, 2018 | Dec. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Cash and cash equivalents | $ 48,058,000 | $ 55,199,000 | $ 48,058,000 | ||
Short-term investments amortized cost | 88,700,000 | ||||
Short-term investments unrealized loss | 200,000 | ||||
Short-term investments fair value | 88,900,000 | ||||
IPO [Member] | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Common stock, shares issued | 364,371 | 9,350,000 | |||
Shire Human Genetic Therapies Inc [Member] | Anti- Dilution Rights [Member] | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Obligation to consummate equity financing | $ 7,000,000 | ||||
Shire Human Genetic Therapies Inc [Member] | Anti- Dilution Rights [Member] | IPO [Member] | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Common stock, shares issued | 183,619 | ||||
Series C Redeemable Convertible Preferred Stock [Member] | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Common stock, shares issued | 21,202,710 | ||||
Common Stock [Member] | Shire Human Genetic Therapies Inc [Member] | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Common stock, shares issued | 1,079,765 | ||||
Common stock value | $ 8,000,000 | ||||
Minimum [Member] | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Short term investments maturity period | 1 year | ||||
Money Market Funds | Fair Value, Inputs, Level 2 | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Cash and cash equivalents | 28,600,000 | $ 23,300,000 | 28,600,000 | ||
Fair Value, Measurements, Recurring | |||||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||||
Fair value,assets transfers from Level 1 to Level 2 | 0 | 0 | 0 | ||
Fair value,assets transfers from Level 2 to Level 1 | 0 | 0 | 0 | ||
Fair Value, assets transfers into (out of) Level 3 | 0 | 0 | |||
Fair value, liabilities transfers from Level 1 to Level 2 | 0 | 0 | 0 | ||
Fair value, liabilities transfers from Level 2 to Level 1 | $ 0 | 0 | 0 | ||
Fair Value, liabilities transfers into (out of) Level 3 | $ 0 | $ 0 |
Fair Value of Financial Asset_5
Fair Value of Financial Assets and Liabilities - Schedule of Unobservable Inputs and Fair Value Components of Contingent Consideration (Detail) - Contingent Consideration $ in Thousands | 12 Months Ended | |
Dec. 31, 2018USD ($) | Dec. 31, 2017USD ($) | |
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Fair Value at | $ 103,642 | $ 81,009 |
Earnout Payments | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Fair Value at | $ 94,999 | $ 72,896 |
Earnout Payments | Minimum [Member] | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Discount Rate | 14.5 | 14.5 |
Projected Year of Payment | 2025 | 2025 |
Earnout Payments | Maximum [Member] | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Discount Rate | 15 | 15 |
Projected Year of Payment | 2039 | 2039 |
Milestone Payments | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Fair Value at | $ 8,643 | $ 6,817 |
Milestone Payments | Minimum [Member] | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Discount Rate | 14.5 | 14.5 |
Projected Year of Payment | 2025 | 2025 |
Milestone Payments | Maximum [Member] | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Discount Rate | 15 | 15 |
Projected Year of Payment | 2030 | 2030 |
Anti- Dilution Rights [Member] | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Fair Value at | $ 1,296 | |
Anti- Dilution Rights [Member] | Minimum [Member] | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Discount Rate | 1.39 | 1.39 |
Anti- Dilution Rights [Member] | Maximum [Member] | ||
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Discount Rate | 1.64 | 1.64 |
Fair Value of Financial Asset_6
Fair Value of Financial Assets and Liabilities - Schedule of Total Acquisition Related Contingent Consideration Liability (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||
Beginning Balance | $ 81,009 | ||
Change in fair value of contingent consideration | $ (14,600) | 25,020 | $ 17,914 |
Ending Balance | 103,642 | 103,642 | 81,009 |
Shire's MRT Program [Member] | |||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||
Ending Balance | $ 10,000 | 10,000 | |
Shire's MRT Program [Member] | Settlement of Contingent Consideration Anti-dilution Liability [Member] | |||
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] | |||
Issuance of common stock in full settlement of contingent consideration anti-dilution liability | $ (2,387) | $ (7,978) |
Property and Equipment, Net - S
Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | $ 15,128 | $ 9,834 |
Less:Accumulated depreciation and amortization | (4,883) | (3,056) |
Property and equipment, net | 10,245 | 6,778 |
Laboratory Equipment [Member] | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | 7,012 | 5,382 |
Computer Equipment [Member] | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | 686 | 481 |
Office Equipment [Member] | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | 836 | 249 |
Leasehold Improvements [Member] | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | 5,635 | 1,131 |
Construction In Progress [Member] | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | $ 959 | $ 2,591 |
Property and Equipment, Net - A
Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Property Plant And Equipment [Abstract] | ||
Depreciation and amortization expense | $ 2.4 | $ 1.5 |
Accrued Expenses - Schedule of
Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Payables And Accruals [Abstract] | ||
Accrued employee compensation and benefits | $ 2,933 | $ 2,252 |
Accrued external research and development expenses | 1,901 | 1,115 |
Accrued consultant and professional fees | 977 | 1,130 |
Other | 736 | 1,391 |
Total accrued expenses | $ 6,547 | $ 5,888 |
Redeemable Convertible Prefer_3
Redeemable Convertible Preferred Stock - Additional Information (Detail) | 1 Months Ended | 12 Months Ended | |||
Dec. 31, 2017USD ($)$ / sharesshares | Dec. 31, 2018USD ($)DirectorInstallment$ / sharesshares | Dec. 31, 2017USD ($)$ / sharesshares | Jul. 02, 2018shares | Dec. 31, 2016shares | |
Temporary Equity [Line Items] | |||||
Redeemable convertible preferred stock, shares authorized | shares | 145,833,064 | 0 | 145,833,064 | ||
Redeemable convertible preferred stock, shares Issued | shares | 142,288,292 | 0 | 142,288,292 | ||
Redeemable convertible preferred stock, shares outstanding | shares | 142,288,292 | 0 | 142,288,292 | ||
Payments of stock issuance costs | $ | $ 4,102,000 | $ 153,000 | |||
Beneficial conversion feature in preferred stock | $ | $ 0 | ||||
Conversion of redeemable convertible preferred stock to common stock, Shares | shares | 25,612,109 | 25,612,109 | 25,612,109 | ||
Conversion of share price per share | $ 0.180 | ||||
Equal annual installments | Installment | 3 | ||||
Minimum [Member] | |||||
Temporary Equity [Line Items] | |||||
Gross proceeds from issuance of common stock | $ | $ 50,000,000 | ||||
Issuance price per share of common stock | $ 13.20 | ||||
Percentage of outstanding redeemable convertible preferred stockholders voting as single class | 60.00% | ||||
Maximum [Member] | |||||
Temporary Equity [Line Items] | |||||
Preferred stock outstanding redemption after written notice | 60 days | ||||
Series A Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Redeemable convertible preferred stock, shares authorized | shares | 36,194,026 | 36,194,026 | |||
Redeemable convertible preferred stock, shares Issued | shares | 36,194,026 | 36,194,026 | |||
Redeemable convertible preferred stock, shares outstanding | shares | 36,194,026 | 36,194,026 | |||
Conversion of redeemable convertible preferred stock to common stock, Shares | shares | 6,514,986 | 6,514,986 | |||
Number of directors entitled to be elected | Director | 2 | ||||
Issuance price per share of common stock | $ 1 | ||||
Conversion of share price per share | $ 5.5555 | ||||
Series B Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Redeemable convertible preferred stock, shares authorized | shares | 59,133,987 | 59,133,987 | |||
Redeemable convertible preferred stock, shares Issued | shares | 59,133,987 | 59,133,987 | |||
Redeemable convertible preferred stock, shares outstanding | shares | 59,133,987 | 59,133,987 | |||
Conversion of redeemable convertible preferred stock to common stock, Shares | shares | 10,644,210 | 10,644,210 | |||
Number of directors entitled to be elected | Director | 1 | ||||
Series C Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Redeemable convertible preferred stock, shares authorized | shares | 50,505,051 | 50,505,051 | |||
Redeemable convertible preferred stock, shares Issued | shares | 46,960,279 | 46,960,279 | |||
Redeemable convertible preferred stock, shares outstanding | shares | 46,960,279 | 46,960,279 | |||
Preferred stock issued and sold | shares | 21,202,710 | 21,202,710 | |||
Common stock issued and sold, per share | $ 1.98 | $ 1.98 | |||
Net proceeds from issuance of redeemable convertible preferred stock | $ | $ 41,900,000 | ||||
Payments of stock issuance costs | $ | $ 100,000 | ||||
Conversion of redeemable convertible preferred stock to common stock, Shares | shares | 8,452,913 | 8,452,913 | |||
Issuance price per share of common stock | $ 1.98 | ||||
Conversion of share price per share | 10.9999 | ||||
Series B-1 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1.0593 | ||||
Conversion of share price per share | 5.8849 | ||||
Series B-2 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1 | ||||
Conversion of share price per share | 5.5555 | ||||
Series B-3 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1.0305 | ||||
Conversion of share price per share | 5.7249 | ||||
Series B-4 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1.0330 | ||||
Conversion of share price per share | 5.7388 | ||||
Series B-5 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1.0381 | ||||
Conversion of share price per share | 5.7672 | ||||
Series B-6 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1.0513 | ||||
Conversion of share price per share | 5.8405 | ||||
Series B-7 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1.0426 | ||||
Conversion of share price per share | 5.7922 | ||||
Series B-8 Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Issuance price per share of common stock | 1.08 | ||||
Conversion of share price per share | $ 5.9999 | ||||
Redeemable Convertible Preferred Stock [Member] | |||||
Temporary Equity [Line Items] | |||||
Redeemable convertible preferred stock, shares outstanding | shares | 142,288,292 | 142,288,292 | 121,085,582 | ||
Cash dividends declared or paid | $ | $ 0 | $ 0 |
Redeemable Convertible Prefer_4
Redeemable Convertible Preferred Stock - Schedule of Redeemable Convertible Preferred Stock (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Jul. 02, 2018 | Dec. 31, 2017 |
Temporary Equity [Line Items] | |||
Redeemable convertible preferred stock, shares authorized | 0 | 145,833,064 | |
Redeemable convertible preferred stock, shares Issued | 0 | 142,288,292 | |
Redeemable convertible preferred stock, shares outstanding | 0 | 142,288,292 | |
Redeemable convertible preferred stock | $ 192,896 | ||
Liquidation Preference | $ 192,374 | ||
Conversion of redeemable convertible preferred stock to common stock, Shares | 25,612,109 | 25,612,109 | |
Series A Redeemable Convertible Preferred Stock [Member] | |||
Temporary Equity [Line Items] | |||
Redeemable convertible preferred stock, shares authorized | 36,194,026 | ||
Redeemable convertible preferred stock, shares Issued | 36,194,026 | ||
Redeemable convertible preferred stock, shares outstanding | 36,194,026 | ||
Redeemable convertible preferred stock | $ 36,194 | ||
Liquidation Preference | $ 36,194 | ||
Conversion of redeemable convertible preferred stock to common stock, Shares | 6,514,986 | ||
Series B Redeemable Convertible Preferred Stock [Member] | |||
Temporary Equity [Line Items] | |||
Redeemable convertible preferred stock, shares authorized | 59,133,987 | ||
Redeemable convertible preferred stock, shares Issued | 59,133,987 | ||
Redeemable convertible preferred stock, shares outstanding | 59,133,987 | ||
Redeemable convertible preferred stock | $ 64,002 | ||
Liquidation Preference | $ 63,199 | ||
Conversion of redeemable convertible preferred stock to common stock, Shares | 10,644,210 | ||
Series C Redeemable Convertible Preferred Stock [Member] | |||
Temporary Equity [Line Items] | |||
Redeemable convertible preferred stock, shares authorized | 50,505,051 | ||
Redeemable convertible preferred stock, shares Issued | 46,960,279 | ||
Redeemable convertible preferred stock, shares outstanding | 46,960,279 | ||
Redeemable convertible preferred stock | $ 92,700 | ||
Liquidation Preference | $ 92,981 | ||
Conversion of redeemable convertible preferred stock to common stock, Shares | 8,452,913 |
Preferred Stock - Additional In
Preferred Stock - Additional Information (Detail) - $ / shares | Dec. 31, 2018 | Jul. 02, 2018 | Dec. 31, 2017 |
Class of Stock [Line Items] | |||
Preferred stock, shares authorized | 10,000,000 | 0 | |
Preferred stock, par value | $ 0.001 | $ 0.001 | |
Preferred stock, shares outstanding | 0 | 0 | |
IPO [Member] | |||
Class of Stock [Line Items] | |||
Preferred stock, shares authorized | 10,000,000 | ||
Preferred stock, par value | $ 0.001 |
Common Stock - Additional Infor
Common Stock - Additional Information (Detail) - USD ($) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Jul. 02, 2018 | |
Class of Stock [Line Items] | |||
Common stock, shares authorized | 200,000,000 | 236,092,611 | 200,000,000 |
Common stock, par value | $ 0.001 | $ 0.001 | |
Common stock voting rights | Each share of common stock entitles the holder to one vote for each share of common stock held. | ||
Cash dividend paid shares | $ 0 | $ 0 | |
2016 Stock Incentive Plan [Member] | |||
Class of Stock [Line Items] | |||
Reserved shares of common stock for conversion of outstanding shares of redeemable convertible preferred stock | 32,115,490 |
Incentive Stock Options and R_3
Incentive Stock Options and Restricted Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | Jun. 15, 2018 | Mar. 07, 2018 | Dec. 31, 2018 | Dec. 31, 2017 |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Common stock, shares issued | 45,139,955 | 9,582,791 | ||
Allocated share based compensation expense | $ 7,333 | $ 3,680 | ||
Unrecognized compensation cost related to unvested stock-based awards | $ 19,600 | |||
Unrecognized compensation cost, period for recognition | 2 years 7 months 6 days | |||
Chief Scientific Officer [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Stock options for purchase of common stock held, exercisable period | 1 year | |||
Allocated share based compensation expense | $ 300 | |||
Options vested for purchase of common stock | 72,871 | |||
Stock options for purchase of common stock held | 204,353 | |||
Stock Options [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of share options granted during the period | 2,169,290 | |||
Intrinsic value of stock options, exercised | $ 100 | |||
Exercise of stock options, Shares | 49,459 | 0 | ||
Weighted average grant-date fair value | $ 5.95 | $ 4.10 | ||
Fair value of options vested | $ 4,900 | $ 2,600 | ||
Restricted Common Stock [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Allocated share based compensation expense | $ 300 | $ 400 | ||
2018 Stock Incentive Plan [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of shares remaining available for issuance | 360,514 | |||
Percentage threshold of outstanding shares under the plan | 4.00% | |||
Number of share options granted during the period | 203,176 | |||
Percentage of exercise price per share of fair market value | 100.00% | |||
Expiration period of stock options after grant date | 10 years | |||
Stock options for purchase of common stock held, exercisable period | 4 years | |||
2018 Stock Incentive Plan [Member] | Minimum [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of stock issued during period under the plan | 3,349,582 | |||
2018 Stock Incentive Plan [Member] | Share-based Compensation Award, Tranche One [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of common shares reserved for issuance | 2,512,187 | |||
2018 Stock Incentive Plan [Member] | Share-based Compensation Award, Tranche Two [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of common shares reserved for issuance | 1,013,167 | |||
2018 Employee Stock Purchase Plan [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of stock issued during period under the plan | 418,697 | |||
Percentage threshold of outstanding shares under the plan | 1.00% | |||
Common stock, shares issued | 0 | |||
2018 Employee Stock Purchase Plan [Member] | Minimum [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of stock issued during period under the plan | 837,395 | |||
2016 Stock Incentive Plan [Member] | ||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||||
Number of common shares reserved for issuance | 32,115,490 | |||
Number of share options granted during the period | 1,966,114 | |||
Percentage of exercise price per share of fair market value | 100.00% | |||
Expiration period of stock options after grant date | 10 years | |||
Stock options for purchase of common stock held, exercisable period | 4 years |
Incentive Stock Options and R_4
Incentive Stock Options and Restricted Stock - Summary of Stock Option Activity (Detail) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Number of shares | ||
Number of shares, beginning balance | 4,364,916 | |
Number of shares, granted | 2,169,290 | |
Number of shares, exercised | (49,459) | 0 |
Number of shares, forfeited | (248,741) | |
Number of shares, ending balance | 6,236,006 | 4,364,916 |
Number of shares, vested, ending balance | 1,827,004 | 661,593 |
Number of shares, vested and expected to vest, ending balance | 6,236,006 | 4,364,916 |
Weighted average exercise price | ||
Weighted average exercise price, beginning balance | $ 7.17 | |
Weighted average exercise price, granted | 8.82 | |
Weighted average exercise price, exercised | 5.62 | |
Weighted average exercise price, forfeited | 6.62 | |
Weighted average exercise price, ending balance | 7.78 | $ 7.17 |
Weighted average exercise price, vested, ending balance | 7.16 | 7.04 |
Weighted average exercise price, vested and expected to vest, ending balance | $ 7.78 | $ 7.17 |
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Remaining Contractual Term Abstract | ||
Weighted average remaining contractual term, ending balance | 8 years 8 months 26 days | 9 years 9 months 14 days |
Weighted average remaining contractual term, vested, ending balance | 7 years 11 months 12 days | 9 years 8 months 19 days |
Weighted average remaining contractual term, vested and expected to vest, ending balance | 8 years 8 months 26 days | 9 years 9 months 14 days |
Intrinsic value | ||
Intrinsic value, ending balance | $ 1,104 | $ 977 |
Intrinsic value, vested, ending balance | 632 | 231 |
Intrinsic value, vested and expected to vest, ending balance | $ 1,104 | $ 977 |
Incentive Stock Option and Rest
Incentive Stock Option and Restricted Stock - Summary of Assumptions Used in Black-Scholes Option-Pricing Model to Determine Grant-Date Fair Value of Stock Option Granted (Detail) - Stock Options [Member] | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Employees and Directors [Member] | ||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Risk-free interest rate | 2.81% | 2.15% |
Expected term (in years) | 6 years | 6 years |
Expected volatility | 75.50% | 59.00% |
Expected dividend yield | 0.00% | 0.00% |
Non-Employee [Member] | ||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Risk-free interest rate | 2.08% | |
Expected term (in years) | 10 years | |
Expected volatility | 60.90% | |
Expected dividend yield | 0.00% |
Incentive Stock Option and Re_2
Incentive Stock Option and Restricted Stock - Summary of Restricted Stock Activity (Detail) - Restricted Common Stock [Member] | 12 Months Ended |
Dec. 31, 2018$ / sharesshares | |
Number of shares | |
Number of shares, beginning balance | shares | 526,478 |
Number of shares, forfeited | shares | (2,446) |
Number of shares, vested | shares | (304,884) |
Number of shares, ending balance | shares | 219,148 |
Weighted average grant-date fair value | |
Weighted average grant-date fair value, beginning balance | $ / shares | $ 1.14 |
Weighted average grant-date fair value, forfeited | $ / shares | 1.28 |
Weighted average grant-date fair value, vested | $ / shares | 1.04 |
Weighted average grant-date fair value, ending balance | $ / shares | $ 1.27 |
Incentive Stock Option and Re_3
Incentive Stock Option and Restricted Stock - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Stock-based compensation expense | $ 7,333 | $ 3,680 |
Research and Development Expenses [Member] | ||
Stock-based compensation expense | 3,756 | 1,886 |
General and Administrative Expenses [Member] | ||
Stock-based compensation expense | $ 3,577 | $ 1,794 |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Operating Loss Carryforwards [Line Items] | ||
Federal corporate income tax rate | 21.00% | 34.00% |
Tax cuts and jobs act of 2017, net operating losses carryforward, maximum percentage of taxable income | 80.00% | |
Tax cuts and jobs act of 2017, change in tax rate income tax expense benefit | $ (6,100,000) | |
Tax cuts and jobs act of 2017, change in tax rate income tax expense benefit due to deferred tax liabilities adjustment | (3,700,000) | |
Tax cuts and jobs act of 2017, change in tax rate income tax expense benefit due to deferred tax assets adjustment | (2,400,000) | |
Tax adjustments to the provisional amounts | 0 | |
Income tax benefits | $ (5,565,000) | (12,481,000) |
orphan drug tax credit carryforwards | $ 6,600,000 | |
Orphan drug tax credit carryforwards expiration year | 2037 | |
Increase in ownership of certain stockholders or public groups in the stock as result of transactions, specified period | 3 years | |
Indefinite-lived net operating loss carryforwards | $ 800,000 | |
Increases/(decreases) in valuation allowance | (18,600,000) | |
Tax cuts and jobs act of 2017, change in tax rate deferred tax assets remeasured at lower federal income tax rate offset | 16,200,000 | |
Deferred tax that could be considered a source of future taxable income for the realization of deferred tax assets | 2,400,000 | |
Deferred tax liabilities related to indefinite-lived IPR&D | 2,109,000 | 8,445,000 |
Deferred tax liabilities | 480,000 | 6,039,000 |
Unrecognized tax benefits | $ 0 | 0 |
Income tax examination, description | The federal and state returns are generally subject to tax examinations for the tax years ended December 31, 2013 to the present. | |
Federal and State Net Operating Loss and Tax Credit Carryforwards [Member] | ||
Operating Loss Carryforwards [Line Items] | ||
Increases/(decreases) in valuation allowance | $ 28,500,000 | |
Federal [Member] | ||
Operating Loss Carryforwards [Line Items] | ||
Operating loss carryforwards | 190,800,000 | |
Operating loss carryforwards subject to expiration | $ 122,100,000 | |
Operating loss carryforwards, expiration date | 2031 | |
Research and development tax credit carryforward, amount | $ 5,100,000 | |
Research and development tax credit carryforward expiration year | 2032 | |
State [Member] | ||
Operating Loss Carryforwards [Line Items] | ||
Operating loss carryforwards | $ 171,700,000 | |
Operating loss carryforwards, expiration date | 2031 | |
Research and development tax credit carryforward, amount | $ 2,000,000 | |
Research and development tax credit carryforward expiration year | 2028 | |
Investment tax credit carryforwards amount | $ 400,000 | |
Investment tax credit carryforward expiration year | 2019 | |
Shire's MRT Program [Member] | ||
Operating Loss Carryforwards [Line Items] | ||
Income tax benefits | $ (5,600,000) | $ (6,400,000) |
Maximum [Member] | ||
Operating Loss Carryforwards [Line Items] | ||
Federal corporate income tax rate | 35.00% | |
Minimum [Member] | ||
Operating Loss Carryforwards [Line Items] | ||
Increase in ownership of certain stockholders or public groups in the stock as result of transactions | 50.00% |
Income Taxes - Schedule of Reco
Income Taxes - Schedule of Reconciliation of U.S. Federal Statutory Income Tax Rate and Effective Income Tax Rate (Detail) | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | ||
U.S. federal statutory income tax rate | (21.00%) | (34.00%) |
State income taxes, net of federal benefit | (6.90%) | (5.40%) |
Research and development tax credits and orphan drug credit | (5.50%) | (4.20%) |
Stock-based compensation | 0.50% | 1.50% |
Other permanent differences | 0.30% | 0.40% |
Remeasurement of deferred taxes due to the Tax Act | 15.90% | |
Change in deferred tax asset valuation allowance | 27.70% | 10.00% |
Other | (0.40%) | |
Effective income tax rate | (5.30%) | (15.80%) |
Income Taxes - Schedule of Comp
Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 |
Deferred tax assets: | |||
Net operating loss carryforwards | $ 50,917 | $ 32,524 | |
Research and development tax credit and orphan drug credit carryforwards | 13,581 | 6,372 | |
Depreciation and amortization | 2,380 | 2,025 | |
Accrued expenses and other | 2,894 | 1,090 | |
Total deferred tax assets | 69,772 | 42,011 | |
Deferred tax liabilities: | |||
Indefinite-lived intangible assets | (2,109) | (8,445) | |
Total deferred tax liabilities | (2,109) | (8,445) | |
Valuation allowance | (68,143) | (39,605) | $ (31,729) |
Net deferred tax liabilities | $ (480) | $ (6,039) |
Income Taxes - Summary of Chang
Income Taxes - Summary of Changes in Valuation Allowance for Deferred Tax Assets (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Valuation Allowance [Line Items] | ||
Valuation allowance at beginning of year | $ (39,605) | $ (31,729) |
Increases/decreases in valuation allowance | 18,600 | |
Valuation allowance at end of year | (68,143) | (39,605) |
Decreases Recorded as Benefit to Income Tax Provision [Member] | ||
Valuation Allowance [Line Items] | ||
Increases/decreases in valuation allowance | 18,628 | |
Increases Recorded to Income Tax Provision [Member] | ||
Valuation Allowance [Line Items] | ||
Increases/decreases in valuation allowance | $ (28,538) | $ (26,504) |
Net Loss per Share - Summary of
Net Loss per Share - Summary of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | ||||||||
Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | |
Numerator: | ||||||||||
Net loss | $ (6,037) | $ (42,646) | $ (27,503) | $ (21,209) | $ (16,091) | $ (18,465) | $ (17,933) | $ (13,954) | $ (97,395) | $ (66,443) |
Accretion of redeemable convertible preferred stock to redemption value | (644) | (719) | ||||||||
Net loss attributable to common stockholders | $ (98,039) | $ (67,162) | ||||||||
Denominator: | ||||||||||
Weighted average common shares outstanding—basic and diluted | 26,945,508 | 7,756,180 | ||||||||
Net loss per share attributable to common stockholders—basic and diluted | $ (0.13) | $ (0.97) | $ (3.04) | $ (2.35) | $ (2.04) | $ (2.40) | $ (2.36) | $ (1.86) | $ (3.64) | $ (8.66) |
Net Loss per Share - Additional
Net Loss per Share - Additional Information (Detail) - shares | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] | ||
Antidilutive securities excluded from computation of basic net loss per share | 6,455,154 | 30,503,503 |
Restricted Common Stock [Member] | ||
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] | ||
Antidilutive securities excluded from computation of basic net loss per share | 219,148 | 526,478 |
Restricted Common Stock [Member] | Weighted Average [Member] | ||
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] | ||
Antidilutive securities excluded from computation of basic net loss per share | 372,301 | 733,134 |
Net Loss per Share - Summary _2
Net Loss per Share - Summary of Potential Common Shares Excluded from Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Detail) - shares | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] | ||
Antidilutive securities excluded from computation of basic net loss per share | 6,455,154 | 30,503,503 |
Stock Options [Member] | ||
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] | ||
Antidilutive securities excluded from computation of basic net loss per share | 6,236,006 | 4,364,916 |
Restricted Common Stock [Member] | ||
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] | ||
Antidilutive securities excluded from computation of basic net loss per share | 219,148 | 526,478 |
Redeemable Convertible Preferred Stock [Member] | ||
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] | ||
Antidilutive securities excluded from computation of basic net loss per share | 25,612,109 |
Commitments and Contingencies -
Commitments and Contingencies - Additional Information (Detail) | 1 Months Ended | 12 Months Ended | |||
Jun. 30, 2017USD ($) | Dec. 31, 2018USD ($) | Dec. 31, 2017USD ($) | Jan. 31, 2017USD ($)Letter_Of_Credit | May 31, 2015USD ($) | |
Loss Contingencies [Line Items] | |||||
Rent expense | $ 3,000,000 | $ 3,100,000 | |||
Research and development | 58,024,000 | 47,023,000 | |||
Research agreement, payable amount | $ 1,901,000 | 1,115,000 | |||
Roche Diagnostics Corporation Master Supply Agreement [Member] | |||||
Loss Contingencies [Line Items] | |||||
Raw material to purchase as percentage of demand | 80.00% | ||||
Agreement extended date | Dec. 31, 2024 | ||||
Commitment Amount | $ 24,000,000 | ||||
Purchase commitments, year 2019 | 9,600,000 | ||||
Purchase commitments, year 2020 | 500,000 | ||||
Purchase commitments, year 2021 | 3,500,000 | ||||
Purchase commitments, year 2022 | 3,500,000 | ||||
Purchase commitments,year 2023 | 3,500,000 | ||||
Purchase commitments, year 2024 | 3,500,000 | ||||
Research and development | 5,000,000 | 1,800,000 | |||
MIT Research Agreement [Member] | |||||
Loss Contingencies [Line Items] | |||||
Research and development | 1,200,000 | 1,200,000 | |||
Research agreement, committed amount | $ 3,100,000 | ||||
Research agreement, expiration period | 2019-10 | ||||
Research agreement, payment | $ 2,500,000 | 1,000,000 | |||
Research agreement, total committed amount | 700,000 | ||||
Research agreement, payable amount | 0 | 200,000 | |||
MIT Exclusive Patent License Agreement [Member] | |||||
Loss Contingencies [Line Items] | |||||
Research and development | 100,000 | 100,000 | |||
Research agreement, total committed amount | 700,000 | 0 | |||
Annual license maintenance payments | 200,000 | ||||
Payments of annual license maintenance fees | 100,000 | 100,000 | |||
MIT Exclusive Patent License Agreement [Member] | Sanofi Pasteur Inc [Member] | |||||
Loss Contingencies [Line Items] | |||||
Upfront payment received | 700,000 | ||||
MIT Exclusive Patent License Agreement [Member] | Milestone Payment One [Member] | |||||
Loss Contingencies [Line Items] | |||||
License agreement, milestone payments | 1,375,000 | ||||
MIT Exclusive Patent License Agreement [Member] | Milestone Payment Two [Member] | |||||
Loss Contingencies [Line Items] | |||||
License agreement, milestone payments | $ 1,250,000 | ||||
Cambridge, Massachusetts [Member] | |||||
Loss Contingencies [Line Items] | |||||
Cash deposit collateral | 700,000 | $ 1,000,000 | |||
Lexington, Massachusetts [Member] | |||||
Loss Contingencies [Line Items] | |||||
Lease expiration period | 2028-04 | ||||
Cash deposit collateral | $ 1,000,000 | $ 1,000,000 | $ 300,000 | ||
Number of letter of credit issued | Letter_Of_Credit | 2 | ||||
Lease extension period | 12 months | ||||
Lease termination notice period | 90 days | ||||
Monthly lease payments | $ 200,000 | ||||
Percentage of annual increase in operating lease | 3.00% | ||||
Maximum [Member] | |||||
Loss Contingencies [Line Items] | |||||
Lease expiration period | 2028-04 | ||||
Maximum [Member] | Lexington, Massachusetts [Member] | |||||
Loss Contingencies [Line Items] | |||||
Lease expiration period | 2019-05 | ||||
Minimum [Member] | Lexington, Massachusetts [Member] | |||||
Loss Contingencies [Line Items] | |||||
Lease expiration period | Nov. 30, 2018 |
Commitments and Contingencies_2
Commitments and Contingencies - Schedule of Future Minimum Lease Payments Due Under Operating Leases (Detail) $ in Thousands | Dec. 31, 2018USD ($) |
Asset Purchase Agreement And Related License Agreement [Abstract] | |
2019 | $ 2,534 |
2020 | 2,610 |
2021 | 2,688 |
2022 | 2,769 |
2023 | 2,852 |
2024 and thereafter | 13,096 |
Total | $ 26,549 |
Related Party Transactions - Ad
Related Party Transactions - Additional Information (Detail) - Board of Directors Chairman [Member] - Consulting Agreement [Member] - USD ($) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2012 | |
Related Party Transaction [Line Items] | |||
Base compensation per year | $ 100,000 | ||
General and administrative expenses | $ 100,000 | $ 100,000 | |
Amount paid for services | 100,000 | 100,000 | |
Amount due to related party | $ 11,250 | $ 20,000 | |
Number of share options granted during the period | 85,170 | ||
Exercise price of options granted | $ 7.39 | ||
Stock options vesting period | 4 years | ||
Grant-date fair value of options granted | $ 4.06 | ||
Aggregate fair value of stock options | $ 300,000 | ||
Maximum [Member] | |||
Related Party Transaction [Line Items] | |||
Annual performance bonus | 25.00% |
Costs Associated with Restruc_3
Costs Associated with Restructuring - Additional Information (Detail) $ in Millions | 1 Months Ended | 12 Months Ended |
Jun. 30, 2017Position | Dec. 31, 2017USD ($) | |
Research and Development Expenses [Member] | ||
Restructuring Cost And Reserve [Line Items] | ||
Employee severance charges related to restructuring | $ | $ 0.5 | |
MRNA Therapeutic Platform [Member] | ||
Restructuring Cost And Reserve [Line Items] | ||
Reduction in workforce due to reorganization | Position | 17 |
Costs Associated with Restruc_4
Costs Associated with Restructuring - Summary of Changes in Accrued Restructuring Costs (Detail) $ in Thousands | 12 Months Ended |
Dec. 31, 2017USD ($) | |
Restructuring And Related Activities [Abstract] | |
Charges | $ 473 |
Payments | $ (473) |
Benefit Plans - Additional Info
Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Compensation And Retirement Disclosure [Abstract] | ||
Employer's discretionary contribution to the plan | $ 0.3 | $ 0.2 |
Selected Quarterly Financial _3
Selected Quarterly Financial Information (Unaudited) - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | ||||||||
Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | |
Selected Quarterly Financial Information [Abstract] | ||||||||||
Collaboration revenue | $ 1,182 | $ 238 | $ 1,420 | |||||||
Total operating expenses | 8,480 | 45,719 | $ 29,062 | $ 22,389 | $ 24,588 | $ 20,836 | $ 18,955 | $ 14,869 | 105,650 | $ 79,248 |
Loss from operations | (7,298) | (45,481) | (29,062) | (22,389) | (24,588) | (20,836) | (18,955) | (14,869) | (104,230) | (79,248) |
Net loss | $ (6,037) | $ (42,646) | $ (27,503) | $ (21,209) | $ (16,091) | $ (18,465) | $ (17,933) | $ (13,954) | $ (97,395) | $ (66,443) |
Net loss per share attributable to common stockholders—basic and diluted | $ (0.13) | $ (0.97) | $ (3.04) | $ (2.35) | $ (2.04) | $ (2.40) | $ (2.36) | $ (1.86) | $ (3.64) | $ (8.66) |
Selected Quarterly Financial _4
Selected Quarterly Financial Information (Unaudited) - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | ||||||||
Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | |
Selected Quarterly Financial Information [Line Items] | ||||||||||
Net loss per share attributable to common stockholders—basic and diluted | $ (0.13) | $ (0.97) | $ (3.04) | $ (2.35) | $ (2.04) | $ (2.40) | $ (2.36) | $ (1.86) | $ (3.64) | $ (8.66) |
Decrease in fair value of contingent consideration | $ 14,600 | $ (25,020) | $ (17,914) | |||||||
Previously Reported [Member] | ||||||||||
Selected Quarterly Financial Information [Line Items] | ||||||||||
Net loss per share attributable to common stockholders—basic and diluted | $ (2.94) | $ (2.31) |