Document and Entity Information
Document and Entity Information - shares | 9 Months Ended | |
Sep. 30, 2018 | Nov. 05, 2018 | |
Document And Entity Information [Abstract] | ||
Document Type | 10-Q | |
Amendment Flag | false | |
Document Period End Date | Sep. 30, 2018 | |
Document Fiscal Year Focus | 2,018 | |
Document Fiscal Period Focus | Q3 | |
Trading Symbol | SPRO | |
Entity Registrant Name | Spero Therapeutics, Inc. | |
Entity Central Index Key | 1,701,108 | |
Current Fiscal Year End Date | --12-31 | |
Entity Filer Category | Non-accelerated Filer | |
Entity Small Business | false | |
Entity Emerging Growth Company | true | |
Entity Ex Transition Period | true | |
Entity Common Stock, Shares Outstanding | 18,187,488 |
CONSOLIDATED BALANCE SHEETS
CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017 |
Current assets: | ||
Cash and cash equivalents | $ 40,480 | $ 87,288 |
Marketable securities | 90,745 | |
Other receivables | 332 | 1,011 |
Tax incentive receivable, current | 944 | 1,932 |
Prepaid expenses and other current assets | 1,222 | 1,828 |
Total current assets | 133,723 | 92,059 |
Property and equipment, net | 2,191 | 1,164 |
Deposits | 206 | 206 |
Restricted cash | 50 | |
Total assets | 136,120 | 93,479 |
Current liabilities: | ||
Accounts payable | 1,364 | 3,470 |
Accrued expenses and other current liabilities | 8,564 | 4,321 |
Derivative liabilities | 223 | 223 |
Deferred rent | 127 | 143 |
Total current liabilities | 10,278 | 8,157 |
Deferred rent, net of current portion | 290 | 365 |
Total liabilities | 10,568 | 8,522 |
Commitments and contingencies (Note 9) | ||
Stockholders' equity: | ||
Preferred stock, $0.001 par value; 10,000,000 shares authorized, 2,220 shares issued and outstanding as of September 30, 2018 and zero shares issued and outstanding as of December 31, 2017 | ||
Common stock, $0.001 par value; 60,000,000 shares authorized as of September 30, 2018 and December 31, 3017; 18,182,494 shares issued and outstanding as of September 30, 2018 and 14,369,182 shares issued and outstanding as of December 31, 2017 | 18 | 14 |
Additional paid-in capital | 253,105 | 181,428 |
Accumulated deficit | (127,903) | (96,840) |
Accumulated other comprehensive loss | (23) | |
Total Spero Therapeutics, Inc. stockholders' equity | 125,197 | 84,602 |
Non-controlling interests | 355 | 355 |
Total stockholders' equity | 125,552 | 84,957 |
Total liabilities and stockholders' equity | $ 136,120 | $ 93,479 |
CONSOLIDATED BALANCE SHEETS (Pa
CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares | Sep. 30, 2018 | Dec. 31, 2017 |
Statement Of Financial Position [Abstract] | ||
Preferred stock, par value | $ 0.001 | $ 0.001 |
Preferred stock, shares authorized | 10,000,000 | 10,000,000 |
Preferred stock, shares/units issued | 2,220 | 0 |
Preferred stock, shares/units outstanding | 2,220 | 0 |
Common stock, par value | $ 0.001 | $ 0.001 |
Common stock, shares authorized | 60,000,000 | 60,000,000 |
Common stock, shares/units issued | 18,182,494 | 14,369,182 |
Common stock, shares/units outstanding | 18,182,494 | 14,369,182 |
CONSOLIDATED STATEMENTS OF OPER
CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Income Statement [Abstract] | ||||
Grant revenue | $ 658 | $ 597 | $ 2,274 | $ 986 |
Operating expenses: | ||||
Research and development | 8,459 | 6,910 | 24,758 | 20,366 |
General and administrative | 3,134 | 3,653 | 9,238 | 8,350 |
Total operating expenses | 11,593 | 10,563 | 33,996 | 28,716 |
Loss from operations | (10,935) | (9,966) | (31,722) | (27,730) |
Other income (expense): | ||||
Change in fair value of derivative liabilities | (2) | 1,547 | ||
Interest income and other income (expense), net | 472 | 124 | 659 | 165 |
Total other income (expense), net | 472 | 122 | 659 | 1,712 |
Net loss | (10,463) | (9,844) | (31,063) | (26,018) |
Less: Net loss attributable to non-controlling interest | (8) | (1,137) | ||
Net loss attributable to Spero Therapeutics, Inc. | (10,463) | (9,836) | (31,063) | (24,881) |
Cumulative dividends on redeemable convertible preferred shares | (2,052) | (5,313) | ||
Accretion of redeemable bridge units and redeemable convertible preferred shares to redemption value | (188) | (1,133) | ||
Net loss attributable to common stockholders of Spero Therapeutics, Inc. | $ (10,463) | $ (12,076) | $ (31,063) | $ (31,327) |
Net loss per share attributable to common stockholders per share, basic and diluted | $ (0.60) | $ (36.02) | $ (2.01) | $ (93.96) |
Weighted average common shares outstanding, basic and diluted: | 17,471,462 | 335,285 | 15,417,087 | 333,402 |
Comprehensive loss: | ||||
Net loss | $ (10,463) | $ (9,844) | $ (31,063) | $ (26,018) |
Other comprehensive gain (loss): | ||||
Unrealized gain (loss) on marketable securities | (8) | (23) | ||
Total other comprehensive gain (loss) | (8) | (23) | ||
Total comprehensive loss | $ (10,471) | $ (9,844) | $ (31,086) | $ (26,018) |
CONSOLIDATED STATEMENTS OF CASH
CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands | 9 Months Ended | |
Sep. 30, 2018 | Sep. 30, 2017 | |
Cash flows from operating activities: | ||
Net loss | $ (31,063) | $ (26,018) |
Adjustments to reconcile net loss to net cash used in operating activities: | ||
Depreciation and amortization | 270 | 264 |
Loss on disposal of fixed assets | 248 | |
Change in fair value of derivative liabilities | (1,547) | |
Share-based compensation | 1,980 | 1,054 |
Unrealized foreign currency transaction (gain) loss | 237 | (93) |
Accretion of discount on marketable securities | (346) | |
Changes in operating assets and liabilities: | ||
Other receivables | 679 | (233) |
Prepaid expenses and other current assets | 706 | 204 |
Tax incentive receivables | 980 | (806) |
Accounts payable | (2,088) | (112) |
Accrued expenses and other current liabilities | 2,372 | 1,011 |
Deferred rent | (91) | (95) |
Net cash used in operating activities | (26,116) | (26,371) |
Cash flows from investing activities: | ||
Purchases of marketable securities | (104,421) | |
Proceeds from maturities of marketable securities | 14,000 | |
Purchases of property and equipment | (22) | |
Net cash used in investing activities | (90,443) | |
Cash flows from financing activities: | ||
Proceeds from stock option exercises | 197 | |
Cash payment for Potentiator non-controlling interests | (1,175) | |
Net cash provided by (used in) financing activities | 69,701 | 41,429 |
Net (decrease) increase in cash and cash equivalents | (46,858) | 15,058 |
Cash, cash equivalents and restricted cash at beginning of period | 87,338 | 10,365 |
Cash, cash equivalents and restricted cash at end of period | 40,480 | 25,423 |
Supplemental disclosure of non-cash investing and financing activities: | ||
Purchases of property and equipment in accrued expenses | 1,628 | 28 |
Deferred offering costs included in accounts payable and accrued expenses | 1,588 | |
Conversion of bridge units into preferred units | 8,500 | |
Settlement of derivative liabilities upon issuance of preferred units | 944 | |
Cumulative dividends on redeemable convertible preferred units | 5,313 | |
Accretion of redeemable convertible preferred units to redemption value | 557 | |
Accretion of bridge units to redemption value | 576 | |
Elimination of non-controlling interest balance upon repurchase of the non-controlling interest | 5,306 | |
2018 Equity Offering [Member] | ||
Cash flows from financing activities: | ||
Proceeds from equity offering | 70,500 | |
Payment of offering costs | $ (996) | |
2017 Initial Public Offering [Member] | ||
Cash flows from financing activities: | ||
Payment of offering costs | (507) | |
Series C Preferred Stock [Member] | ||
Cash flows from financing activities: | ||
Proceeds from issuance of preferred units, net of issuance costs | $ 43,111 |
Nature of the Business and Basi
Nature of the Business and Basis of Presentation | 9 Months Ended |
Sep. 30, 2018 | |
Accounting Policies [Abstract] | |
Nature of the Business and Basis of Presentation | 1. Nature of the Business and Basis of Presentation Spero Therapeutics, Inc., together with its consolidated subsidiaries (the “Company”), is a multi-asset, clinical-stage biopharmaceutical company focused on identifying, developing and commercializing novel treatments for multi-drug resistant (“MDR”) bacterial infections. The Company’s most advanced product candidate, SPR994, is designed to be the first broad-spectrum oral carbapenem-class antibiotic for use in adults to treat MDR Gram-negative infections. Treatment with effective orally administrable antibiotics may prevent hospitalizations for serious infections and enable earlier, more convenient and cost-effective treatment of patients after hospitalization. The Company also has a platform technology known as its Potentiator Platform that it believes will enable it to develop drugs that will expand the spectrum and potency of existing antibiotics, including formerly inactive antibiotics, against Gram-negative bacteria. The Company’s lead product candidates generated from its Potentiator Platform are two intravenous, or IV,-administered agents, SPR741 and SPR206, designed to treat MDR Gram-negative infections in the hospital setting. In addition, the Company is developing SPR720, an oral antibiotic designed for the treatment of pulmonary non-tuberculous mycobacterial infections. The Company believes that its novel product candidates, if successfully developed and approved, would have a meaningful patient impact and significant commercial applications for the treatment of MDR infections in both the community and hospital settings. The Company was formed as Spero Therapeutics, LLC in December 2013 under the laws of the State of Delaware. On June 30, 2017, through a series of transactions, Spero Therapeutics, LLC merged with and into Spero Therapeutics, Inc. (formerly known as Spero OpCo, Inc.), a Delaware corporation. As part of the transactions, holders of preferred units and common units of Spero Therapeutics, LLC exchanged their units for shares of Spero Therapeutics, Inc. on a one-for-one basis. These transactions are collectively referred to as the Reorganization. Upon completion of the Reorganization, the historical consolidated financial statements of Spero Therapeutics, LLC became the historical consolidated financial statements of Spero Therapeutics, Inc. because the Reorganization was accounted for as a reorganization of entities under common control. The Company is subject to risks and uncertainties 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. On October 20, 2017, the Company effected a one-for-6.0774 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 then outstanding Preferred Stock. 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 adjustment of the preferred stock conversion ratios. In addition, all common units and incentive units as well as the conversion ratios of preferred units of Spero Therapeutics, LLC have been presented as if the reverse stock split of the common stock of Spero Therapeutics, Inc. had been applied to such units and ratios of Spero Therapeutics, LLC. On November 6, 2017, the Company completed an initial public offering (“IPO”) of its common stock, and issued and sold 5,500,000 shares of common stock at a public offering price of $14.00 per share, resulting in net proceeds of $71.6 million after deducting underwriting discounts and commissions but before deducting offering costs. On November 14, 2017, Spero Therapeutics, Inc., issued and sold an additional 471,498 shares of its common stock at the IPO price of $14.00 per share pursuant to the underwriters’ partial exercise of their option to purchase additional shares of common stock, resulting in additional net proceeds of $6.1 million after deducting underwriting discounts and commissions. Aggregate net proceeds from the IPO totaled $74.2 million after deducting underwriting discounts, commissions and offering costs. On July 17, 2018, the Company completed an underwritten public offering of its common and preferred stock, which resulted in the sale of 3,780,000 shares of common stock at a price of $12.50 per share, and 2,220 shares of Series A Convertible Preferred Stock at a price of $12,500 per share. Each share of Series A Convertible Preferred Stock sold in the offering is convertible into 1,000 shares of the Company’s common stock. The Company received net proceeds from the offering of approximately $70.5 million after deducting underwriting discounts and commissions but before deducting $1.0 million of offering expenses payable by the Company. In accordance with Accounting Standards Update (“ASU”) 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40) The accompanying consolidated financial statements of the Company have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its consolidated subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Interim Financial Information The consolidated balance sheet at December 31, 2017 was derived from audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited consolidated financial statements as of September 30, 2018, and for the three and nine months ended September 30, 2018 and 2017, have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2017, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, on file with SEC. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2018, and results of operations for the three and nine months ended September 30, 2018 and 2017, and cash flows for the nine months ended September 30, 2018 and 2017 have been made. The results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2018. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 9 Months Ended |
Sep. 30, 2018 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Use of Estimates The preparation of 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 financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, revenue recognition, the accrual for research and development expenses, the valuation of common shares prior to the Company’s completion of its IPO, the valuation of share-based awards and the valuation of derivative liabilities. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions. Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company considers its investment portfolio of investments to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Investments with maturities beyond one year are generally classified as short term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other income (expense), net based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers various factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. Fair Value Measurements Certain assets and liabilities 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 and 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 derivative liabilities are carried at fair value, determined according to the fair value hierarchy described above (see Note 3). The carrying values of the Company’s accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities. Derivative Liabilities In connection with certain equity financings, licensing transactions and research collaborations, the Company has identified certain embedded and freestanding derivatives, which are recorded as liabilities on the Company’s consolidated balance sheet and are remeasured to fair value at each reporting date until the derivative is settled. Changes in the fair value of the derivative liabilities are recognized as other income (expense) in the consolidated statement of operations and comprehensive loss. Net Income (Loss) per Share Attributable to Spero Therapeutics, Inc. 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. Net income (loss) per share attributable to common stockholders is calculated based on net income (loss) attributable to Spero Therapeutics, Inc. and excludes net income (loss) attributable to non-controlling interests. 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 common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents. 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, such losses are not allocated to such participating securities. In periods in which the Company reports a net loss attributable to common stockholders of Spero Therapeutics, Inc., diluted net loss per share attributable to common stockholders of Spero Therapeutics, Inc. is the same as basic net loss per share attributable to common stockholders of Spero Therapeutics, Inc., since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common stockholders of Spero Therapeutics, Inc. for the three and nine months ended September 30, 2018 and 2017. Recently Issued and Adopted Accounting Pronouncements In May 2014, the FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which supersedes existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The standard outlines a five-step process to achieve this principle, and will require companies to use more judgment and make more estimates than under the current guidance. The Company expects that these judgments and estimates will include identifying performance obligations in the customer contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which delays the effective date of ASU 2014-09 such that the standard is effective for public entities for annual periods beginning after December 15, 2017 and for interim periods within those fiscal years. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (“ASU 2016-08”), which further clarifies the implementation guidance on principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensin g, clarifying the implementation guidance on identifying performance obligations and licensing. Specifically, the amendments in this update reduce the cost and complexity of identifying promised goods or services and improve the guidance for determining whether promises are separately identifiable. The amendments in this update also provide implementation guidance on determining whether an entity’s promise to grant a license provides a customer with either a right to use the entity’s intellectual property (which is satisfied at a point in time) or a right to access the entity’s intellectual property (which is satisfied over time). In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients (“ASU 2016-12”), which clarifies the objective of the collectability criterion, presentation of taxes collected from customers, non-cash consideration, contract modifications at transition, completed contracts at transition and how guidance in ASU 2014-09 is retrospectively applied. ASU 2016-08, ASU 2016-10 and ASU 2016-12 have the same effective dates and transition requirements as ASU 2014-09. The Company adopted this standard using the modified retrospective approach, however the Company determined that government grant revenue is outside the scope of ASC 606. Therefore, the adoption of ASC 606 did not impact the Company’s financial position, results of operations or cash flows as its only existing revenue source as of September 30, 2018 is government grants. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842 Codification Improvements to Topic 842, Leases Leases (Topic 842): Targeted Improvements In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU 2016-18 Statement of Cash Flows (Topic 230) The inclusion of restricted cash increased the beginning and ending balances of the unaudited condensed consolidated statement of cash flows by $50,000 for the nine months ended September 30, 2017. In January 2017, FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting In July 2017, the FASB issued ASU 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) I. Accounting for Certain Financial Instruments with Down Round Features II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (Topic 718) – Improvements to Nonemployee Share-Based Payment Accounting |
Fair Value Measurements and Mar
Fair Value Measurements and Marketable Securities | 9 Months Ended |
Sep. 30, 2018 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurements and Marketable Securities | 3. Fair Value Measurements and Marketable Securities The following tables present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis (in thousands): Fair Value Measurements at September 30, 2018 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ — $ 29,896 $ — $ 29,896 U.S. government securities — 5,994 — 5,994 Total cash equivalents — 35,890 — 35,890 Marketable securities: U.S. government securities — 38,761 — 38,761 U.S. corporate bonds — 35,594 — 35,594 U.S. commercial paper — 16,390 — 16,390 Total marketable securities — 90,745 — 90,745 Total cash equivalents and marketable securities $ — $ 126,635 $ — $ 126,635 Derivative liabilities: Anti-dilution rights $ — $ — $ 223 $ 223 Total derivative liabilities $ — $ — $ 223 $ 223 Fair Value Measurements at December 31, 2017 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ — $ 83,121 $ — $ 83,121 $ — $ 83,121 $ — $ 83,121 Derivative liabilities: Anti-dilution rights $ — $ — $ 223 $ 223 $ — $ — $ 223 $ 223 During the three and nine months ended September 30, 2018 and 2017, there were no transfers between Level 1, Level 2 and Level 3 categories. Marketable Securities The Company’s marketable securities are classified as Level 2 assets under the fair value hierarchy as these assets were primarily determined from independent pricing sources, which generally derive security prices from recently reported trades for identical or similar securities. The following table summarizes the gross unrealized gains and losses of the Company’s marketable securities as of September 30, 2018 (in thousands): September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Assets: U.S. government securities $ 38,771 $ 1 $ (11 ) $ 38,761 U.S. corporate bonds 35,607 1 (14 ) 35,594 U.S. commercial paper 16,390 — — 16,390 $ 90,768 $ 2 $ (25 ) $ 90,745 As of September 30, 2018, all of the Company’s marketable securities had remaining contractual maturity dates of one year or less from the consolidated balance sheet date. The Company did not own any marketable securities as of December 31, 2017. Anti-Dilution Rights In connection with the issuance of non-controlling interests in certain of the Company’s subsidiaries (see Note 8), specifically Spero Potentiator, Inc., Spero Europe, Ltd. and Spero Gyrase, Inc., the Company granted anti-dilution rights to the minority investors. The Company classifies the anti-dilution rights as a derivative liability on its consolidated balance sheet because they are freestanding instruments that represent a conditional obligation to issue a variable number of shares. The Company remeasures the derivative liability associated with the anti-dilution rights to fair value at each reporting date, and recognizes changes in the fair value of the derivative liability as a component of other income (expense) in the consolidated statement of operations and comprehensive loss. The fair value of these derivative liabilities was determined using a discounted cash flow model. As of September 30, 2018 and December 31, 2017, the Company’s fair value of the anti-dilution rights relates only to the anti-dilution rights held by the minority investor in Spero Gyrase, Inc., as detailed below. Spero Gyrase, Inc. In March 2016, in connection with the issuance of a non-controlling interest in its subsidiary, Spero Gyrase, Inc. (“Spero Gyrase”), to Biota Pharmaceuticals, Inc. (now Aviragen Therapeutics, Inc.) (“Aviragen”), the Company granted to Aviragen certain anti-dilution rights (see Note 8). The fair value of the derivative liability related to the anti-dilution rights upon issuance in March 2016 was $1.6 million. The most significant assumption impacting the fair value of the anti-dilution rights was the probability that the Company would fund the maximum amount of investment providing anti-dilution protection. Upon issuance of the rights and through December 31, 2016, the probability of such funding was determined to be 100%. During 2017, the probability of such funding was reduced to 0% due to the Company’s decision to no longer pursue development of the acquired technology. The fair value of the derivative liability decreased accordingly by $1.4 million to $0.2 million by June 30, 2017. As of September 30, 2018 and December 31, 2017, the value of the derivative liability of $0.2 million represents amounts funded to the entity that could be settled by the issuance of equity. |
Accrued Expenses and Other Curr
Accrued Expenses and Other Current Liabilities | 9 Months Ended |
Sep. 30, 2018 | |
Payables And Accruals [Abstract] | |
Accrued Expenses and Other Current Liabilities | 4. Accrued Expenses and Other Current Liabilities September 30, 2018 December 31, 2017 Accrued external research and development expenses $ 4,146 $ 1,770 Accrued payroll and related expenses 1,622 1,369 Accrued professional fees 727 878 Accrued manufacturing equipment 1,559 — Accrued other 510 304 $ 8,564 $ 4,321 |
Convertible Preferred Shares
Convertible Preferred Shares | 9 Months Ended |
Sep. 30, 2018 | |
Equity [Abstract] | |
Convertible Preferred Shares | 5. Convertible Preferred Shares Series A Convertible Preferred Shares The Company’s amended and restated certificate of incorporation authorizes its Board of Directors to issue up to 10,000,000 shares of preferred stock, par value $0.001 per share. As part of the Company’s July 2018 underwritten public offering, 2,220 shares were designated as Series A Convertible Preferred Stock and issued at a price of $12,500 per share. Each share of Series A Convertible Preferred Stock is convertible into 1,000 shares of the Company’s common stock at any time at the option of the holder, provided that the holder will be prohibited from converting the Series A Convertible Preferred Stock into shares of common stock if, as a result of such conversion, the holder, together with its affiliates, would own more than 9.99% of the total number of shares of the Company’s common stock then issued and outstanding. In the event of the Company’s liquidation, dissolution, or winding up, holders of Series A Convertible Preferred Stock will receive a payment equal to $0.001 per share of Series A Convertible Preferred Stock, plus an additional amount equal to any dividends declared but unpaid on such shares, any of our securities that by their terms are junior to the Series A Preferred Stock Redeemable Convertible Preferred Shares Prior to the Reorganization, the operating agreement of Spero Therapeutics, LLC, as amended and restated, provided for the issuance of Junior preferred units, Class A preferred units, Class B preferred units and bridge units, but did not specify an authorized number of each for issuance. Subsequent to the Company’s Reorganization on June 30, 2017 (see Note 1), the Company’s amended and restated certificate of incorporation authorized the issuance of 43,297,267 shares of preferred stock, par value $0.001 per share, and holders of outstanding preferred units of Spero Therapeutics, LLC exchanged their units for preferred stock of Spero Therapeutics, Inc. on a one-for-one basis. The rights and preferences of each class of stock were the same both before and after the Reorganization. On October 20, 2017, the Company effected a one-for-6.0774 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion rations for each series or the Company’s Preferred Stock. Upon the closing of the Company’s IPO in November 2017, all of the then outstanding convertible preferred shares automatically converted into shares of common stock. In March 2017, the Company issued and sold 24,326,470 Class C preferred units at a price of $1.7749 per unit for proceeds of $43.0 million, net of issuance costs of $0.2 million. The sale of Class C preferred units met the definition of a qualified financing under the 2016 bridge unit agreements. The Company issued 5,321,112 Class C preferred units upon the conversion of the 2016 bridge units in the amount of $8.5 million, at a conversion price of $1.60 per unit, which represented a discount of 10% to the price per unit paid by other investors in the Class C preferred unit financing. The conversion was accounted for as an extinguishment for accounting purposes. Accordingly, the Company recorded the Class C preferred units issued upon conversion of the 2016 bridge units at their aggregate fair value of $9.4 million and recorded a corresponding adjustment to extinguish the then-current carrying value of the 2016 bridge units of $8.5 million and the then-current fair value of the derivative liability related to the contingent prepayment option associated with the 2016 bridge units of $0.9 million. There was no gain or loss recognized upon the extinguishment. In July 2017 the Company sold to its Chief Financial Officer 61,880 shares of the Company’s Series C preferred stock at a price of $1.7749 per share, for proceeds of $0.1 million. |
Common Stock
Common Stock | 9 Months Ended |
Sep. 30, 2018 | |
Equity [Abstract] | |
Common Stock | 6. Common Stock On July 17, 2018, the Company completed an underwritten public offering of its common and preferred stock, which resulted in the sale of 3,780,000 shares of common stock at a price of $12.50 per share, and 2,220 shares of Series A Convertible Preferred Stock at a price of $12,500 per share. The Company received net proceeds from the offering of approximately $70.5 million after deducting underwriting discounts and commissions but before deducting $1.0 million of offering expenses payable by the Company. |
Share-Based Compensation
Share-Based Compensation | 9 Months Ended |
Sep. 30, 2018 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Share-Based Compensation | 7. Share-Based Compensation On June 28, 2017, the Company’s stockholders approved the 2017 Stock Incentive Plan (the “2017 Plan”). The 2017 Plan provides for the grant of incentive stock options, nonqualified stock options, stock grants and stock-based awards. The 2017 Plan is administered by the board of directors, or at the discretion of the board of directors, by a committee of the board. The exercise prices, vesting and other restrictions are determined at the discretion of the board of directors, or their committee if so delegated, except that the exercise price per share of stock options may not be less than 100% of the fair market value of the share of common stock on the date of grant and the term of stock option may not be greater than ten years. The number of shares initially reserved for issuance under the 2017 Plan was 1,785,416 shares of common stock. The shares of common stock underlying any awards that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2017 Plan will be added back to the shares of common stock available for issuance under the 2017 Plan. On October 18, 2017, the Company’s stockholders approved an amendment to the 2017 Plan, which became effective upon the completion of the Company’s IPO, to increase the total number of shares reserved for issuance under the 2017 Plan from 1,785,416 to 2,696,401. Additionally, the number of shares of common stock that may be issued under the 2017 Plan will automatically increase on each January 1, beginning with the fiscal year ending December 31, 2019 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027, equal to the lowest of (i) 607,324 shares of common stock, (ii) 4% of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors or compensation committee. There were 322,730 options granted during the nine months ended September 30, 2018. As of September 30, 2018, there were 2,186,378 options outstanding under the 2017 Plan and 476,711 shares remaining available to be issued under the 2017 Plan. The Company recorded share-based compensation expense in the following expense categories of its consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Research and development expenses $ 252 $ 202 $ 789 $ 249 General and administrative expenses 453 729 1,191 805 Total $ 705 $ 931 $ 1,980 $ 1,054 |
Non-Controlling Interests
Non-Controlling Interests | 9 Months Ended |
Sep. 30, 2018 | |
Noncontrolling Interest [Abstract] | |
Non-Controlling Interests | 8. Non-Controlling Interests Spero Potentiator In February 2015, the Company’s wholly owned subsidiary, Spero Potentiator, issued 996 shares of its common stock with an aggregate fair value of $1.1 million to Northern Antibiotics Oy Ltd. (“Northern”) in exchange for an exclusive license to develop and commercialize certain licensed compounds and licensed products. In connection with the acquisition of the license, Northern obtained anti-dilution rights to maintain its 49.9% ownership percentage in Spero Potentiator at no additional cost to Northern in the event that Spero Potentiator completed subsequent equity financings, subject to a maximum amount of such financings. The Company accounted for the anti-dilution rights as a derivative liability on its consolidated balance sheet. The fair value of the derivative liability associated with the anti-dilution rights upon issuance in February 2015 of $2.4 million was recorded as research and development expenses as it was deemed to represent additional consideration for the license. In November 2015, Northern was issued an additional 2,736 common shares of Spero Potentiator for no additional cost as a result of the anti-dilution rights. The Company valued these shares at $1.5 million and recorded the amount as an increase in the non-controlling interest and a reduction in the carrying value of the derivative liability. In January and August 2016, Northern was issued an additional 2,160 common shares of Spero Potentiator for no additional cost. The Company valued these shares at $1.0 million and recorded the amount as an increase in the non-controlling interest and a reduction of the derivative liability. At that time, the anti-dilution rights issued to Northern were fully settled as Northern had received the maximum number of shares it was entitled to under the anti-dilution rights. In June 2017, the Company repurchased all of the shares of Spero Potentiator held by Northern in exchange for a cash payment of $1.0 million and contingent consideration of $0.1 million. As a condition of the repurchase of the shares from Northern, the Company amended the license agreement with Northern such that the Company will be obligated to make milestone payments of up to $7.0 million upon the achievement of specified clinical, commercial and other milestones, including a payment of $2.5 million upon the closing of an IPO, which occurred and was paid in November 2017. As a result of this transaction, during the six months ended June 30, 2017, the Company reclassified the balance of the non-controlling interest of $6.4 million as of the date of the transaction to accumulated deficit as an increase to that account. Additionally, the cash payment of $1.0 million was recorded as an increase to accumulated deficit. The Company will record the contingent payments as research and development expense when it becomes probable that the payments will be due. For periods subsequent to the acquisition, the Company no longer reports a non-controlling interest related to Spero Potentiator. Spero Europe In January 2016, the Company entered into an agreement with Promiliad Biopharma Inc. (“Promiliad”), whereby Promiliad granted to Spero Europe certain know-how and a sublicense to research, develop, manufacture and sell certain compounds. In exchange for the know-how and sublicense, Spero Europe provided Promiliad with a 5% equity ownership interest in Spero Europe, with a fair value of $0.1 million. In addition, Spero Europe agreed to make payments to Promiliad upon the achievement of future regulatory and commercial milestones of $4.1 million and to pay to Promiliad royalties of a mid single-digit percentage on net sales of licensed products under the agreement. Spero had the right to terminate the agreement with thirty days’ notice. The Company recognized research and development expense of $0.1 million upon the acquisition of the license and recorded a non-controlling interest in Spero Europe in a corresponding amount. In connection with the acquisition of the license, Promiliad obtained anti-dilution rights to maintain their 5% equity ownership in Spero Europe at no additional cost to Promiliad in the event that Spero Europe completed subsequent funding events, subject to a maximum amount of such funding of $5.0 million. The Company accounted for the anti-dilution rights as a derivative liability on its consolidated balance sheet. The fair value of the derivative liability associated with the anti-dilution rights upon issuance in January 2016 of $0.2 million was recorded as research and development expenses as it was deemed to represent additional consideration for the license. In May 2017, the Company repurchased all of the shares of Spero Europe from Promiliad in exchange for the return of the license. As a result of the transaction, the Company reclassified the balance of the non-controlling interest in Spero Europe of less than $0.1 million as of the date of the transaction to accumulated deficit as an increase to that account. For periods subsequent to the repurchase, the Company no longer reports a non-controlling interest related to Spero Europe. Spero Gyrase In March 2016, the Company entered into an agreement with Aviragen and its affiliates in order to acquire certain intellectual property and know-how related to certain compounds. In connection with the transaction, the Company established Spero Gyrase, a Delaware corporation, and issued to Aviragen 200 common shares of Spero Gyrase with a fair value of $1.1 million, which represented a 20% equity ownership interest in Spero Gyrase. In addition, Spero Gyrase agreed to make future milestone and royalty payments in exchange for the intellectual property. The Company accounted for the acquisition of technology as an asset acquisition because it did not meet the definition of a business. The Company recorded the acquired technology as research and development expense in the consolidated statement of operations and comprehensive loss in the amount of $1.1 million, because the acquired technology had not reached commercial feasibility and had no alternative future use, and recorded a non-controlling interest in Spero Gyrase in a corresponding amount. In connection with the agreement, Aviragen obtained anti-dilution rights to maintain their 20% equity ownership of Spero Gyrase at no additional cost to Aviragen in the event that Spero Gyrase completed subsequent funding events, subject to a maximum amount of such funding of $8.0 million. The Company accounted for the anti-dilution rights as a derivative liability on its consolidated balance sheet (see Note 3). The fair value of the derivative liability associated with the anti-dilution rights upon issuance in March 2016 of $1.6 million was recorded as research and development expenses as it was deemed to represent additional consideration for the license. Spero Cantab In June 2016, the Company entered into a stock purchase agreement and related agreements (the “Cantab Agreements”) with Pro Bono Bio PLC, a corporation organized under the laws of England, and certain of its affiliates, including PBB Distributions Limited (“PBB”), Cantab Anti-Infectives Ltd. (“CAI”) and New Pharma License Holdings Limited (“NPLH”) in order to acquire NPLH and its intellectual property rights and assets relating to the Company’s Potentiator Platform. Under the Cantab Agreements, CAI agreed to submit a request to NIAID to novate the CAI-held NIAID contract to the Company. The NIAID contract provides for development funding of up to $6.3 million over a base and three option periods. To date, funding for the base period and the first two option periods totaling $5.7 million had been committed to CAI. Novation of the NIAID contract to the Company was finalized in December 2017. The Company shall pay PBB a percentage of funds received from NIAID up to a maximum of $1.3 million. Consideration under Cantab Agreements consisted of: (i) 125 shares of Spero Cantab, the Company’s subsidiary, which represented a 12.5% ownership interest in Spero Cantab, and anti-dilution rights (as described below) issued to PBB, with a combined fair value of $1.6 million, (ii) upfront consideration of $0.3 million (to be credited against future payments payable to CAI), (iii) contingent milestone payments due upon the achievement of certain clinical, regulatory and commercial milestones (see Note 11), (iv) royalty payments of low single-digit percentages based on net sales of products from the licensed technology, and (v) a specified portion of funding payments made by NIAID. The Company accounted for the acquisition of NPLH as an asset acquisition because NPLH did not meet the definition of a business. The Company recognized research and development expense of $1.6 million upon the acquisition of NPLH because the acquired technology had not reached commercial feasibility and had no alternative future use. Upon the issuance of the shares and anti-dilution rights, the Company recorded a non-controlling interest in Spero Cantab of $1.6 million. The $0.3 million payment was recognized as research and development expenses as the services were performed by CAI. The Company records the contingent payments outlined in (iii), (iv) and (v) as research and development expense when it becomes probable that the payments will be due. Novation of the NIAID contract to Spero was finalized in December 2017. Prior to the contract novation, CAI performed research and development services at the Company’s direction and applied for reimbursement from NIAID. The Company paid CAI for such research and development services at an agreed-upon rate which took into consideration costs incurred by CAI, amounts reimbursed to CAI by NIAID and the portion of the NIAID reimbursement the Company paid to CAI. In connection with the Cantab Agreements, PBB obtained anti-dilution rights to maintain a certain equity ownership, ranging from 5% to 12.5%, of Spero Cantab at no additional cost to PBB in the event that Spero Cantab completed subsequent funding events, subject to maximum amount of such funding of $8.0 million. These anti-dilution rights represent a conditional obligation to issue a variable number of shares but are not freestanding and, therefore, do not require bifurcation for accounting purposes from the 125 shares issued. In July 2017, the Company repurchased all of the outstanding shares of Spero Cantab owned by PBB in exchange for a cash payment of $0.2 million and an amendment to the licensing agreement to increase the first two contingent milestone payments by a total of $0.1 million. For periods subsequent to the repurchase, the Company no longer reports a non-controlling interest related to Spero Cantab. As of September 30, 2018 and December 31, 2017, the Company’s only remaining non-controlling interest relates to Spero Gyrase, Inc., which totaled $0.4 million. |
Commitments and Contingencies
Commitments and Contingencies | 9 Months Ended |
Sep. 30, 2018 | |
Commitments And Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 9. Commitments and Contingencies License Agreements The Company has entered into license agreements with various parties under which it is obligated to make contingent and non-contingent payments (see Note 11). Operating Leases In August 2015, the Company entered into an operating lease agreement with U.S. REIF Central Plaza Massachusetts, LLC (the “Landlord”) with respect to its corporate headquarters located at 675 Massachusetts Avenue, Cambridge, Massachusetts (the “Original Lease”).The term of the Original Lease commenced in January 2016 and was scheduled to expire in December 2020. The Original Lease required annual payments of $0.4 million over the initial five-year term. The Original Lease provided for a renewal option to extend its term for an additional five years. Under the terms of the Original Lease, the Company provided a security deposit of $0.2 million to the Landlord, which is included in long-term assets in the accompanying consolidated balance sheets. The Original Lease provided for annual rent escalations as well as tenant incentives in the amount of $0.7 million, of which $0.3 million would be reimbursed to the Landlord over the initial term of the Original Lease. In July 2016, the Company entered into an agreement to lease laboratory space through November 30, 2019 from a sublessor, which requires annual lease payments of $0.3 million, subject to certain escalations. On January 17, 2018, the Company entered into an amendment (the “Amendment”) to the Original Lease. The Amendment makes certain changes to the Original Lease, including (i) the addition of approximately 7,800 square feet of office space in the same building (the “Expansion Premises”) and (ii) an extension of the expiration date of the Original Lease to seven years following the delivery date of the Expansion Premises (the “Lease Term”), which is estimated to be December 1, 2018. Under the Amendment, the Company has two consecutive options to extend the Lease Term for an additional period of five years (the “Option Terms”), subject to certain conditions, upon notice to the Landlord. The Amendment provides for annual base rent for the Expansion Premises of approximately $0.5 million in the first year of the Lease Term, which increases on an annual basis to approximately $0.6 million in the final year of the Lease Term, and annual base rent during the Option Terms to be calculated based on the Landlord’s good faith determination of 100% of the fair market rate for such Option Terms. The Company is also obligated to pay the Landlord certain costs, taxes and operating expenses, subject to certain exclusions. The Amendment also includes a provision from the landlord of $0.4 million for leasehold improvements on the Expansion Premises. Rent escalations and tenant incentives for operating leases are included in deferred rent in the consolidated balance sheet, and rent expense is recognized on a straight-line basis over the terms of occupancy. The following table summarizes the future minimum payments due under the operating leases as of September 30, 2018 (in thousands): Years Ending December 31, 2018 (remainder) $ 248 2019 1,323 2020 1,016 2021 957 2022 1,076 Thereafter 2,200 $ 6,820 Rent expense during the three months ended September 30, 2018 and 2017 was $0.2 million. Rent expense during the nine months ended September 30, 2018 and 2017 was $0.6 million. 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 September 30, 2018 or December 31, 2017. Legal Proceedings The Company is not currently party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings. |
Government Contracts
Government Contracts | 9 Months Ended |
Sep. 30, 2018 | |
Contractors [Abstract] | |
Government Contracts | 10. Government Contracts BARDA In July 2018, the Company was awarded a contract from Biomedical Advanced Research and Development Authority (“BARDA”) of up to $44.2 million to develop SPR994 for the treatment of complicated urinary tract infections (“cUTIs”) caused by antibiotic resistant Gram-negative bacteria and for assessment against biodefense pathogens. The award commits initial funding of $15.7 million over a three-year base period from July 1, 2018 to June 30, 2021 for cUTI development activities. The balance of the award is subject to BARDA exercising two options. The exercise of the first option would entail funding of $13.6 million and is exercisable by BARDA subject to the Company achieving specified milestones related to, among other things, clinical progress and data. The exercise of the second option would entail funding of $14.9 million and is exercisable by BARDA subject to, among other things, satisfactory progress and results from the biodefense studies described below. The Company recognized $0.2 million of revenue under this award during the three and nine months ended September 30, 2018. As part of an inter-agency collaboration between BARDA and the Defense Threat Reduction Agency (“DTRA”), a series of studies to assess the efficacy of SPR994 in the treatment of infections caused by biodefense threats such as anthrax, plague and melioidosis will be conducted by the U.S. Army Medical Research Institute of Infectious Diseases (“USAMRIID”) under the direction of Spero. Because the FDA requires data from a human pneumonic disease as supportive of use of an antibiotic to treat a biothreat infection, the scope of the BARDA award includes the assessment of SPR994 levels in the lung of healthy volunteers as well as a proof of concept clinical trial in pneumonia patients, an indication for which tebipenem, SPR994's active pharmaceutical ingredient, is currently approved in Japan for pediatric use. U.S. Department of Defense In September 2016, the Company was awarded a cooperative agreement with the DoD to further develop anti-infective agents to combat Gram-negative bacteria. The agreement is structured as a single, two-year $1.5 million award. The Company is eligible for the full funding from the DoD, and there are no options to be exercised at a later date. The DoD funding supports next-generation potentiator discovery and screening of SPR741 partners. The Company recognizes revenue under this agreement as qualifying expenses are incurred. The Company recognized less than $0.1 million and $0.2 million of revenue under this agreement during the three and nine months ended September 30, 2018, respectively, and $0.1 million and $0.4 million during the three and nine months ended September 30, 2017, respectively. NIAID In February 2017, the Company was awarded a grant from NIAID under its Small Business Innovation Research program, to conduct additional preclinical studies of SPR720, the Company’s novel oral bacterial gyrase inhibitor, for the treatment of non-tuberculous mycobacterial infections. The award is structured as a 12-month $0.6 million base period and a $0.4 million option period. Through December 31, 2017, only the base period funds had been committed. The Company recognized $0.1 million of revenue in the three and nine months ended September 30, 2017 under this agreement. In June 2016, the Company entered into agreements with Pro Bono Bio PLC (“PBB”), a corporation organized under the laws of England, and certain of its affiliates, including PBB Distributions Limited and Cantab Anti-Infectives Limited (“CAI”), in order to acquire certain intellectual property and government funding arrangements relating to SPR206 (see Note 11). Under these agreements, CAI agreed to submit a request to NIAID to assign the CAI-held NIAID contract to Spero, which was finalized in December 2017. The NIAID contract provides for total development funding of up to $6.3 million, including a base period and three option periods. To date, funding for the base period and the first two option periods totaling $5.7 million have been committed. Spero shall pay PBB a percentage of funds received from NIAID up to a maximum of $1.3 million, of which $0.3 million was paid upfront to PBB as part of this agreement. The Company recognized $0.4 million and $1.1 million of revenue under this agreement during the three and nine months ended September 30, 2018. During the three and nine months ended September 30, 2018, the Company recorded approximately $0.1 million and $0.4 million, respectively, in expense associated with amounts payable to PBB under this agreement, which has been included within research and development expenses within the consolidated statement of operations and comprehensive loss. CARB-X In April 2017, the Company was awarded a grant from CARB-X, a public-private partnership funded by BARDA within the U.S. Department of Health and Human Services to be used to screen, identify and complete Phase 1 trials with at least one partner compound for SPR741, one of the Company’s Potentiator Platform product candidates. The award committed to funding of $1.5 million over a 12-month period. On March 12, 2018, CARB-X committed an additional $0.4 million related to the first option for a period from December 1, 2017 to March 31, 2018. There will be no additional options exercised under the CARB-X award. The Company recognized zero and $0.5 million of revenue during the three and nine months ended September 30, 2018, respectively, under this agreement. The Company recognized $0.4 million and $0.5 million of revenue during the three and nine months ended September 30, 2017, respectively, under this agreement. |
Collaboration and License Agree
Collaboration and License Agreements | 9 Months Ended |
Sep. 30, 2018 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Collaboration and License Agreements | 11. Collaboration and License Agreements The Company has certain obligations under license agreements with third parties that include annual maintenance fees and payments that are contingent upon achieving various development, regulatory and commercial milestones. Pursuant to these license agreements, the Company is required to make milestone payments if certain development, regulatory and commercial milestones are achieved, and may have certain additional research funding obligations. Also, pursuant to the terms of each of these license agreements, when and if commercial sales of a product commence, the Company will pay royalties to its licensors on net sales of the respective products. Aviragen Agreement Under the Company’s agreement with Aviragen (see Note 8) for certain intellectual property and know-how relating to developing a gyrase inhibitor to develop therapies for Gram-negative infections, the Company is obligated to make milestone payments of up to an aggregate of $12.0 Cantab License Agreement Under the Cantab Agreements (see Note 8), the Company is obligated to make milestone payments of up to $5.8 million upon the achievement of specified clinical and regulatory milestones and a payment of £5.0 million ($6.5 million and $6.7 million as of September 30, 2018 and December 31, 2017, respectively) upon the achievement of a specified commercial milestone. In addition, the Company has agreed to pay to PBB royalties, on a product-by-product and country-by-country basis, of a low single-digit percentage based on net sales of products licensed under the agreement. The Cantab Agreements continue indefinitely, with royalty payment obligations thereunder continuing on a product-by-product and country-by-country basis until the later of ten years after the first commercial sale of such product in such country or the expiration in such country of the last to expire valid claim of any of the applicable patents. Vertex License Agreement In May 2016, the Company entered into an agreement with Vertex Pharmaceuticals Incorporated (“Vertex”) whereby Vertex granted the Company certain know-how and a sublicense to research, develop, manufacture and sell products for a proprietary compound, as well as a transfer of materials. In exchange for the know-how, sublicense and materials, Spero paid Vertex an upfront, one-time, nonrefundable, non-creditable fee of $0.5 million, which was recognized as research and development expense. As part of the agreement, the Company is obligated to make future milestone payments of up to $81.1 million upon the achievement of specified clinical, regulatory and commercial milestones and to pay Vertex tiered royalties, on a product-by-product and country-by-country basis, of a mid single-digit to low double-digit percentage based on net sales of products licensed under the agreement. The agreement continues in effect until the expiration of all payment obligations thereunder, with royalty payment obligations continuing on a product-by-product and country-by-country basis until the later of ten years after the first commercial sale of such product in such country or the date of expiration in such country of the last to expire applicable patent. Further, Vertex has the right to terminate the agreement if provided with notification from the Company of intent to cease all development or if no material development or commercialization efforts occur for one year. Meiji License Agreement In June 2017, the Company entered into agreements with Meiji Seika Pharma Co. Ltd. (“Meiji”), a Japanese corporation, whereby Meiji granted to the Company certain know-how and a license to research, develop, manufacture and sell products for a proprietary compound in the licensed territory. In exchange for the know-how and license, the Company paid Meiji an upfront, one-time, nonrefundable, non-creditable fee of $0.6 million, which was recognized as research and development expense. As part of the agreement, the Company is obligated to make milestone payments of up to $3.0 million upon the achievement of specified clinical and regulatory milestones, to pay royalties, on a product-by-product and country-by-country basis, of a low single-digit percentage based on net sales of products licensed under the agreement and to pay Meiji a low double-digit percentage of any sublicense fees received by the Company up to $7.5 million. In October 2017, the Company paid a $1.0 million milestone payment to Meiji upon the enrollment of the first patient in the Company’s Phase 1 clinical trial of SPR994. The payment was recorded as research and development expense in the statement of operations and comprehensive loss for the year ended December 31, 2017. Additionally, the Company will pay Meiji approximately $1.6 million during the fourth quarter of 2018 related to fixed assets which will be used in manufacturing related activities at Meiji. This equipment has been capitalized as property and equipment in the consolidated balance sheet as of September 30, 2018. The agreement continues in effect until the expiration of all payment obligations thereunder (including royalty payments and licensee revenue) on a product-by-product and country-by-country basis, unless earlier terminated by the parties. Pursuant to the terms of the agreement, in addition to each party’s right to terminate the agreement upon the other party’s material breach (if not cured within a specified period after receipt of notice) or insolvency, the Company also has unilateral termination rights (i) in the event that the Company abandons the development and commercialization of SPR994 for efficacy, safety, legal or business factors, and (ii) under certain circumstances arising out of the head license with a global pharmaceutical company. Northern License Agreement In June 2017, in connection with the repurchase of all of the outstanding shares of Spero Potentiator (see Note 8), the Company amended its license agreement with Northern such that the Company agreed to pay Northern up to $7.0 million upon the achievement of specified clinical, regulatory and other milestones, including a total payment of $2.5 million upon the closing of an initial public offering. In addition, under an exchange agreement the Company entered into with Northern, the Company is obligated to make a payment to Northern of $0.1 million upon the closing of an initial public offering. The agreement has a perpetual term and no express termination rights. Upon the closing of the Company’s IPO in November 2017, the Company paid $2.6 million to Northern in connection with both the license and exchange agreements. This payment was recorded as research and development expense in the Company’s statement of operations and comprehensive loss for the year ended December 31, 2017. |
Australia Research and Developm
Australia Research and Development Tax Incentive | 9 Months Ended |
Sep. 30, 2018 | |
Research And Development [Abstract] | |
Australia Research and Development Tax Incentive | 12. Australia Research and Development Tax Incentive The Australian government has established a research and development tax incentive to encourage industry investment in research and development, which is available to companies incorporated under Australian law that have core research and development activities. In September 2016, the Company established Spero Potentiator Australia Pty Limited to carry out certain research and development activities. As this subsidiary meets the eligibility requirements of the Australian tax law, it is eligible to receive a 43.5% tax incentive for qualified research and development activities. The Company recorded $0.3 million and a reduction to research and development expenses in the consolidated statements of operations and comprehensive loss during both the three and nine months ended September 30, 2018, respectively, associated with this tax incentive, representing 43.5% of the Company’s qualified research and development spending in Australia. |
Net Loss per Share
Net Loss per Share | 9 Months Ended |
Sep. 30, 2018 | |
Earnings Per Share [Abstract] | |
Net Loss per Share | 13. Net Loss per Share Basic and diluted net loss per share attributable to common stockholders of Spero Therapeutics, Inc. was calculated as follows (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Net loss $ (10,463 ) $ (9,844 ) $ (31,063 ) $ (26,018 ) Less: Net loss attributable to non-controlling interests — (8 ) — (1,137 ) Plus: Cumulative dividends on redeemable convertible preferred shares — (2,052 ) — (5,313 ) Plus: Accretion of bridge units and redeemable convertible preferred shares to redemption value — (188 ) — (1,133 ) Net loss attributable to common stockholders of Spero Therapeutics, Inc. $ (10,463 ) $ (12,076 ) $ (31,063 ) $ (31,327 ) Denominator: Weighted average common shares outstanding, basic and diluted 17,471,462 335,285 15,417,087 333,402 Net loss per share attributable to common stockholders of Spero Therapeutics, Inc., basic and diluted $ (0.60 ) $ (36.02 ) $ (2.01 ) $ (93.96 ) The Company excluded potentially dilutive securities from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders of Spero Therapeutics, Inc. is the same. The Company excluded the following potential common shares, 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: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Options to purchase common stock 2,186,378 1,541,474 2,186,378 1,541,474 Series A Convertible Preferred Stock (as converted to common shares) 2,220,000 — 2,220,000 — Redeemable convertible preferred shares (as converted to common shares) — 8,062,403 — 8,062,403 4,406,378 9,603,877 4,406,378 9,603,877 |
Subsequent Events
Subsequent Events | 9 Months Ended |
Sep. 30, 2018 | |
Subsequent Events [Abstract] | |
Subsequent Events | 14. Subsequent Events The Company has evaluated, for potential recognition and disclosure, events that occurred prior to the date at which the condensed consolidated financial statements were available to be issued. There were no material subsequent events. |
Summary of Significant Accoun_2
Summary of Significant Accounting Policies (Policies) | 9 Months Ended |
Sep. 30, 2018 | |
Accounting Policies [Abstract] | |
Interim Financial Information | Interim Financial Information The consolidated balance sheet at December 31, 2017 was derived from audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited consolidated financial statements as of September 30, 2018, and for the three and nine months ended September 30, 2018 and 2017, have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2017, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, on file with SEC. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2018, and results of operations for the three and nine months ended September 30, 2018 and 2017, and cash flows for the nine months ended September 30, 2018 and 2017 have been made. The results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2018. |
Use of Estimates | Use of Estimates The preparation of 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 financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, revenue recognition, the accrual for research and development expenses, the valuation of common shares prior to the Company’s completion of its IPO, the valuation of share-based awards and the valuation of derivative liabilities. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions. |
Cash Equivalents | Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. |
Marketable Securities | Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days. The Company considers its investment portfolio of investments to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Investments with maturities beyond one year are generally classified as short term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other income (expense), net based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers various factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. |
Fair Value Measurements | Fair Value Measurements Certain assets and liabilities 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 and 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 derivative liabilities are carried at fair value, determined according to the fair value hierarchy described above (see Note 3). The carrying values of the Company’s accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities. |
Derivative Liabilities | Derivative Liabilities In connection with certain equity financings, licensing transactions and research collaborations, the Company has identified certain embedded and freestanding derivatives, which are recorded as liabilities on the Company’s consolidated balance sheet and are remeasured to fair value at each reporting date until the derivative is settled. Changes in the fair value of the derivative liabilities are recognized as other income (expense) in the consolidated statement of operations and comprehensive loss. |
Net Income (Loss) per Share Attributable to Spero Therapeutics, Inc. | Net Income (Loss) per Share Attributable to Spero Therapeutics, Inc. 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. Net income (loss) per share attributable to common stockholders is calculated based on net income (loss) attributable to Spero Therapeutics, Inc. and excludes net income (loss) attributable to non-controlling interests. 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 common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of common stock equivalents. 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, such losses are not allocated to such participating securities. In periods in which the Company reports a net loss attributable to common stockholders of Spero Therapeutics, Inc., diluted net loss per share attributable to common stockholders of Spero Therapeutics, Inc. is the same as basic net loss per share attributable to common stockholders of Spero Therapeutics, Inc., since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. The Company reported a net loss attributable to common stockholders of Spero Therapeutics, Inc. for the three and nine months ended September 30, 2018 and 2017. |
Recently Issued and Adopted Accounting Pronouncements | Recently Issued and Adopted Accounting Pronouncements In May 2014, the FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which supersedes existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The standard outlines a five-step process to achieve this principle, and will require companies to use more judgment and make more estimates than under the current guidance. The Company expects that these judgments and estimates will include identifying performance obligations in the customer contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which delays the effective date of ASU 2014-09 such that the standard is effective for public entities for annual periods beginning after December 15, 2017 and for interim periods within those fiscal years. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (“ASU 2016-08”), which further clarifies the implementation guidance on principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensin g, clarifying the implementation guidance on identifying performance obligations and licensing. Specifically, the amendments in this update reduce the cost and complexity of identifying promised goods or services and improve the guidance for determining whether promises are separately identifiable. The amendments in this update also provide implementation guidance on determining whether an entity’s promise to grant a license provides a customer with either a right to use the entity’s intellectual property (which is satisfied at a point in time) or a right to access the entity’s intellectual property (which is satisfied over time). In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients (“ASU 2016-12”), which clarifies the objective of the collectability criterion, presentation of taxes collected from customers, non-cash consideration, contract modifications at transition, completed contracts at transition and how guidance in ASU 2014-09 is retrospectively applied. ASU 2016-08, ASU 2016-10 and ASU 2016-12 have the same effective dates and transition requirements as ASU 2014-09. The Company adopted this standard using the modified retrospective approach, however the Company determined that government grant revenue is outside the scope of ASC 606. Therefore, the adoption of ASC 606 did not impact the Company’s financial position, results of operations or cash flows as its only existing revenue source as of September 30, 2018 is government grants. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842 Codification Improvements to Topic 842, Leases Leases (Topic 842): Targeted Improvements In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments In November 2016, the FASB issued ASU 2016-18 Statement of Cash Flows (Topic 230) The inclusion of restricted cash increased the beginning and ending balances of the unaudited condensed consolidated statement of cash flows by $50,000 for the nine months ended September 30, 2017. In January 2017, FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting In July 2017, the FASB issued ASU 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) I. Accounting for Certain Financial Instruments with Down Round Features II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (Topic 718) – Improvements to Nonemployee Share-Based Payment Accounting |
Fair Value Measurements and M_2
Fair Value Measurements and Marketable Securities (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Fair Value Disclosures [Abstract] | |
Summary of Financial Assets and Liabilities Measured at Fair Value Recurring Basis | The following tables present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis (in thousands): Fair Value Measurements at September 30, 2018 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ — $ 29,896 $ — $ 29,896 U.S. government securities — 5,994 — 5,994 Total cash equivalents — 35,890 — 35,890 Marketable securities: U.S. government securities — 38,761 — 38,761 U.S. corporate bonds — 35,594 — 35,594 U.S. commercial paper — 16,390 — 16,390 Total marketable securities — 90,745 — 90,745 Total cash equivalents and marketable securities $ — $ 126,635 $ — $ 126,635 Derivative liabilities: Anti-dilution rights $ — $ — $ 223 $ 223 Total derivative liabilities $ — $ — $ 223 $ 223 Fair Value Measurements at December 31, 2017 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ — $ 83,121 $ — $ 83,121 $ — $ 83,121 $ — $ 83,121 Derivative liabilities: Anti-dilution rights $ — $ — $ 223 $ 223 $ — $ — $ 223 $ 223 |
Summary of Gross Unrealized Gains and Losses of Marketable Securities | The following table summarizes the gross unrealized gains and losses of the Company’s marketable securities as of September 30, 2018 (in thousands): September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Assets: U.S. government securities $ 38,771 $ 1 $ (11 ) $ 38,761 U.S. corporate bonds 35,607 1 (14 ) 35,594 U.S. commercial paper 16,390 — — 16,390 $ 90,768 $ 2 $ (25 ) $ 90,745 |
Accrued Expenses and Other Cu_2
Accrued Expenses and Other Current Liabilities (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Payables And Accruals [Abstract] | |
Schedule of Accrued Expenses and Other Current Liabilities | September 30, 2018 December 31, 2017 Accrued external research and development expenses $ 4,146 $ 1,770 Accrued payroll and related expenses 1,622 1,369 Accrued professional fees 727 878 Accrued manufacturing equipment 1,559 — Accrued other 510 304 $ 8,564 $ 4,321 |
Share-Based Compensation (Table
Share-Based Compensation (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Summary of Share-Based Compensation Expense | The Company recorded share-based compensation expense in the following expense categories of its consolidated statements of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Research and development expenses $ 252 $ 202 $ 789 $ 249 General and administrative expenses 453 729 1,191 805 Total $ 705 $ 931 $ 1,980 $ 1,054 |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 9 Months Ended |
Sep. 30, 2018 | |
Commitments And Contingencies Disclosure [Abstract] | |
Summary of Future Minimum Payments Due Under Operating Leases | The following table summarizes the future minimum payments due under the operating leases as of September 30, 2018 (in thousands): Years Ending December 31, 2018 (remainder) $ 248 2019 1,323 2020 1,016 2021 957 2022 1,076 Thereafter 2,200 $ 6,820 |
Net Loss per Share (Tables)
Net Loss per Share (Tables) | 9 Months Ended |
Sep. 30, 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 of Spero Therapeutics, Inc. was calculated as follows (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Numerator: Net loss $ (10,463 ) $ (9,844 ) $ (31,063 ) $ (26,018 ) Less: Net loss attributable to non-controlling interests — (8 ) — (1,137 ) Plus: Cumulative dividends on redeemable convertible preferred shares — (2,052 ) — (5,313 ) Plus: Accretion of bridge units and redeemable convertible preferred shares to redemption value — (188 ) — (1,133 ) Net loss attributable to common stockholders of Spero Therapeutics, Inc. $ (10,463 ) $ (12,076 ) $ (31,063 ) $ (31,327 ) Denominator: Weighted average common shares outstanding, basic and diluted 17,471,462 335,285 15,417,087 333,402 Net loss per share attributable to common stockholders of Spero Therapeutics, Inc., basic and diluted $ (0.60 ) $ (36.02 ) $ (2.01 ) $ (93.96 ) |
Summary of Shares Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders | The Company excluded the following potential common shares, 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: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Options to purchase common stock 2,186,378 1,541,474 2,186,378 1,541,474 Series A Convertible Preferred Stock (as converted to common shares) 2,220,000 — 2,220,000 — Redeemable convertible preferred shares (as converted to common shares) — 8,062,403 — 8,062,403 4,406,378 9,603,877 4,406,378 9,603,877 |
Nature of the Business and Ba_2
Nature of the Business and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands | Jul. 17, 2018USD ($)$ / sharesshares | Nov. 14, 2017USD ($)$ / sharesshares | Nov. 06, 2017USD ($)$ / sharesshares | Oct. 20, 2017 | Nov. 30, 2017USD ($) | Sep. 30, 2018USD ($)shares | Sep. 30, 2017USD ($) | Sep. 30, 2018USD ($)shares | Sep. 30, 2017USD ($) | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) |
Nature Of Business And Basis Of Presentation [Line Items] | |||||||||||
Entity incorporation month and year | 2013-12 | ||||||||||
State of incorporation | Delaware | ||||||||||
Merger date | Jun. 30, 2017 | ||||||||||
Business combination exchange ratio | 1 | ||||||||||
Net loss | $ 10,463 | $ 9,836 | $ 31,063 | $ 24,881 | $ 38,700 | $ 25,500 | |||||
Accumulated deficit | $ 127,903 | $ 127,903 | $ 96,840 | ||||||||
Underwritten Public Offering [Member] | |||||||||||
Nature Of Business And Basis Of Presentation [Line Items] | |||||||||||
Net proceeds from issuance of common stock | $ 70,500 | ||||||||||
Offering expenses payable | $ 1,000 | ||||||||||
Underwritten Public Offering [Member] | Series A Convertible Preferred Stock [Member] | |||||||||||
Nature Of Business And Basis Of Presentation [Line Items] | |||||||||||
Issuance of stock, shares | shares | 2,220 | ||||||||||
Share price | $ / shares | $ 12,500 | ||||||||||
Convertible preferred stock, description | Each share of Series A Convertible Preferred Stock sold in the offering is convertible into 1,000 shares of the Company’s common stock. | ||||||||||
Number of shares issuable upon conversion | shares | 1,000 | 1,000 | 1,000 | ||||||||
Common Stock [Member] | |||||||||||
Nature Of Business And Basis Of Presentation [Line Items] | |||||||||||
Reverse stock split ratio | 0.164544 | ||||||||||
Reverse stock split | One-for-6.0774 | ||||||||||
Net proceeds from issuance of common stock | $ 6,100 | $ 71,600 | $ 74,200 | ||||||||
Common Stock [Member] | Initial Public Offering [Member] | |||||||||||
Nature Of Business And Basis Of Presentation [Line Items] | |||||||||||
Issuance of stock, shares | shares | 471,498 | 5,500,000 | |||||||||
Share price | $ / shares | $ 14 | $ 14 | |||||||||
Common Stock [Member] | Underwritten Public Offering [Member] | |||||||||||
Nature Of Business And Basis Of Presentation [Line Items] | |||||||||||
Issuance of stock, shares | shares | 3,780,000 | ||||||||||
Share price | $ / shares | $ 12.50 |
Summary of Significant Accoun_3
Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) | 9 Months Ended | |
Sep. 30, 2018 | Sep. 30, 2017 | |
Summary Of Significant Accounting Policies [Line Items] | ||
Cash, cash equivalents increased due to inclusion | $ (46,858,000) | $ 15,058,000 |
Accounting Standards Update 2016-18 [Member] | ||
Summary Of Significant Accounting Policies [Line Items] | ||
Cash, cash equivalents increased due to inclusion | $ 50,000 |
Fair Value Measurements and M_3
Fair Value Measurements and Marketable Securities - Summary of Financial Assets and Liabilities Measured at Fair Value Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017 |
Cash equivalents: | ||
Total cash equivalents | $ 35,890 | |
Marketable securities: | ||
Total marketable securities | 90,745 | |
Total cash equivalents and marketable securities | 126,635 | $ 83,121 |
Derivative liabilities: | ||
Derivative liabilities | 223 | 223 |
Anti- dilution Rights [Member] | ||
Derivative liabilities: | ||
Derivative liabilities | 223 | 223 |
Money Market Funds [Member] | ||
Cash equivalents: | ||
Total cash equivalents | 29,896 | 83,121 |
U.S. Government Securities [Member] | ||
Cash equivalents: | ||
Total cash equivalents | 5,994 | |
Marketable securities: | ||
Total marketable securities | 38,761 | |
U.S. Corporate Bonds [Member] | ||
Marketable securities: | ||
Total marketable securities | 35,594 | |
U.S. Commercial Paper [Member] | ||
Marketable securities: | ||
Total marketable securities | 16,390 | |
Level 2 [Member] | ||
Cash equivalents: | ||
Total cash equivalents | 35,890 | |
Marketable securities: | ||
Total marketable securities | 90,745 | |
Total cash equivalents and marketable securities | 126,635 | 83,121 |
Level 2 [Member] | Money Market Funds [Member] | ||
Cash equivalents: | ||
Total cash equivalents | 29,896 | 83,121 |
Level 2 [Member] | U.S. Government Securities [Member] | ||
Cash equivalents: | ||
Total cash equivalents | 5,994 | |
Marketable securities: | ||
Total marketable securities | 38,761 | |
Level 2 [Member] | U.S. Corporate Bonds [Member] | ||
Marketable securities: | ||
Total marketable securities | 35,594 | |
Level 2 [Member] | U.S. Commercial Paper [Member] | ||
Marketable securities: | ||
Total marketable securities | 16,390 | |
Level 3 [Member] | ||
Derivative liabilities: | ||
Derivative liabilities | 223 | 223 |
Level 3 [Member] | Anti- dilution Rights [Member] | ||
Derivative liabilities: | ||
Derivative liabilities | $ 223 | $ 223 |
Fair Value Measurements and M_4
Fair Value Measurements and Marketable Securities - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended | ||||
Sep. 30, 2018 | Sep. 30, 2017 | Jun. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2016 | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||||||
Fair value assets level 1 to level 2 transfers | $ 0 | $ 0 | $ 0 | $ 0 | ||||
Fair value assets level 2 to level 1 transfers | 0 | 0 | 0 | 0 | ||||
Fair value liabilities level 1 to level 2 transfers | 0 | 0 | 0 | 0 | ||||
Fair value liabilities level 2 to level 1 transfers | 0 | 0 | 0 | 0 | ||||
Transfer of financial asset into level 3 of fair value | 0 | 0 | 0 | 0 | ||||
Transfer of financial liabilities into level 3 of fair value | 0 | $ 0 | 0 | $ 0 | ||||
Spero Gyrase, Inc. [Member] | Anti- dilution Rights [Member] | ||||||||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||||||||
Derivative liabilities | $ 200,000 | $ 200,000 | $ 200,000 | $ 200,000 | $ 1,600,000 | |||
Fair value inputs probability of funding | 0.00% | 100.00% | ||||||
Decrease in derivative liability | $ 1,400,000 |
Fair Value Measurements and M_5
Fair Value Measurements and Marketable Securities - Summary of Gross Unrealized Gains and Losses of Marketable Securities (Detail) $ in Thousands | Sep. 30, 2018USD ($) |
Schedule Of Available For Sale Securities [Line Items] | |
Amortized Cost | $ 90,768 |
Gross Unrealized Gains | 2 |
Gross Unrealized Losses | (25) |
Fair Value | 90,745 |
U.S. Government Securities [Member] | |
Schedule Of Available For Sale Securities [Line Items] | |
Amortized Cost | 38,771 |
Gross Unrealized Gains | 1 |
Gross Unrealized Losses | (11) |
Fair Value | 38,761 |
U.S. Corporate Bonds [Member] | |
Schedule Of Available For Sale Securities [Line Items] | |
Amortized Cost | 35,607 |
Gross Unrealized Gains | 1 |
Gross Unrealized Losses | (14) |
Fair Value | 35,594 |
U.S. Commercial Paper [Member] | |
Schedule Of Available For Sale Securities [Line Items] | |
Amortized Cost | 16,390 |
Fair Value | $ 16,390 |
Accrued Expenses and Other Cu_3
Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017 |
Payables And Accruals [Abstract] | ||
Accrued external research and development expenses | $ 4,146 | $ 1,770 |
Accrued payroll and related expenses | 1,622 | 1,369 |
Accrued professional fees | 727 | 878 |
Accrued manufacturing equipment | 1,559 | |
Accrued other | 510 | 304 |
Accrued expenses and other current liabilities | $ 8,564 | $ 4,321 |
Convertible Preferred Shares -
Convertible Preferred Shares - Additional Information (Detail) | Jul. 17, 2018USD ($)$ / sharesshares | Oct. 20, 2017 | Jun. 30, 2017$ / sharesshares | Jul. 31, 2017USD ($)$ / sharesshares | Mar. 31, 2017USD ($)$ / sharesshares | Sep. 30, 2018$ / sharesshares | Sep. 30, 2017USD ($) | Dec. 31, 2016USD ($)$ / sharesshares | Dec. 31, 2017$ / sharesshares |
Class Of Stock [Line Items] | |||||||||
Preferred stock, shares authorized | shares | 10,000,000 | 10,000,000 | |||||||
Preferred stock, par value | $ / shares | $ 0.001 | $ 0.001 | |||||||
Share conversion ratio | 1 | ||||||||
Conversion of bridge units in to preferred units | $ 8,500,000 | ||||||||
Common Stock [Member] | |||||||||
Class Of Stock [Line Items] | |||||||||
Reverse stock split ratio | 0.164544 | ||||||||
Reverse stock split | One-for-6.0774 | ||||||||
Redeemable Convertible Preferred Shares [Member] | |||||||||
Class Of Stock [Line Items] | |||||||||
Redeemable convertible shares, authorized | shares | 43,297,267 | ||||||||
Redeemable convertible shares, par value | $ / shares | $ 0.001 | ||||||||
Redeemable Convertible Preferred Shares [Member] | Class C Preferred Units [Member] | |||||||||
Class Of Stock [Line Items] | |||||||||
Redeemable convertible shares, par value | $ / shares | $ 1.7749 | ||||||||
Redeemable convertible shares issued and sold | shares | 24,326,470 | 5,321,112 | |||||||
Proceeds from issuance of preferred units, net of issuance costs | $ 43,000,000 | ||||||||
Payment of offering costs | $ 200,000 | ||||||||
Preferred units discount percentage | 10.00% | ||||||||
Conversion of bridge units in to preferred units | $ 8,500,000 | ||||||||
Conversion price of redeemable preferred share | $ / shares | $ 1.60 | ||||||||
Convertible debt fair value disclosures | $ 9,400,000 | ||||||||
Liability fair value adjustment | 8,500,000 | ||||||||
Redeemable issuer option value | 900,000 | ||||||||
Gain on extinguishment | $ 0 | ||||||||
Redeemable Convertible Preferred Shares [Member] | Class C Preferred Units [Member] | Chief Financial Officer [Member] | |||||||||
Class Of Stock [Line Items] | |||||||||
Redeemable convertible shares, par value | $ / shares | $ 1.7749 | ||||||||
Redeemable convertible shares issued and sold | shares | 61,880 | ||||||||
Proceeds from issuance of preferred units, net of issuance costs | $ 100,000 | ||||||||
Underwritten Public Offering [Member] | |||||||||
Class Of Stock [Line Items] | |||||||||
Payment of offering costs | $ 1,000,000 | ||||||||
Underwritten Public Offering [Member] | Common Stock [Member] | |||||||||
Class Of Stock [Line Items] | |||||||||
Issuance of stock, shares | shares | 3,780,000 | ||||||||
Share price | $ / shares | $ 12.50 | ||||||||
Underwritten Public Offering [Member] | Series A Convertible Preferred Stock [Member] | |||||||||
Class Of Stock [Line Items] | |||||||||
Issuance of stock, shares | shares | 2,220 | ||||||||
Share price | $ / shares | $ 12,500 | ||||||||
Number of shares issuable upon conversion | shares | 1,000 | 1,000 | |||||||
Percentage of shares owned by share holders | 9.99% | ||||||||
Preferred stock, liquidation per share | $ / shares | $ 0.001 | ||||||||
Voting rights | no |
Common Stock - Additional Infor
Common Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions | Jul. 17, 2018 | Nov. 14, 2017 | Nov. 06, 2017 | Nov. 30, 2017 |
Underwritten Public Offering [Member] | ||||
Class Of Stock [Line Items] | ||||
Net proceeds from issuance of common stock | $ 70.5 | |||
Offering expenses payable | $ 1 | |||
Series A Convertible Preferred Stock [Member] | Underwritten Public Offering [Member] | ||||
Class Of Stock [Line Items] | ||||
Issuance of stock, shares | 2,220 | |||
Share price | $ 12,500 | |||
Common Stock [Member] | ||||
Class Of Stock [Line Items] | ||||
Net proceeds from issuance of common stock | $ 6.1 | $ 71.6 | $ 74.2 | |
Common Stock [Member] | Underwritten Public Offering [Member] | ||||
Class Of Stock [Line Items] | ||||
Issuance of stock, shares | 3,780,000 | |||
Share price | $ 12.50 |
Share-Based Compensation - Addi
Share-Based Compensation - Additional Information (Detail) - 2017 Plan [Member] - shares | Jun. 28, 2017 | Sep. 30, 2018 | Oct. 18, 2017 | Oct. 17, 2017 |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Number of shares authorized for issuance | 1,785,416 | 2,696,401 | 1,785,416 | |
Number of shares to be incremented | 607,324 | |||
Percentage of outstanding shares of common stock to be incremented | 4.00% | |||
Options granted | 322,730 | |||
Options outstanding | 2,186,378 | |||
Common stock available for issuance | 476,711 | |||
Minimum [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Exercise price per share of stock options as a percentage of fair market value of share of common stock | 100.00% | |||
Options vesting period | 10 years |
Share-Based Compensation - Summ
Share-Based Compensation - Summary of Share-Based Compensation Expense (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Share-based compensation expense | $ 705 | $ 931 | $ 1,980 | $ 1,054 |
Research and Development Expenses [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Share-based compensation expense | 252 | 202 | 789 | 249 |
General and Administrative Expenses [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Share-based compensation expense | $ 453 | $ 729 | $ 1,191 | $ 805 |
Non-Controlling Interests - Spe
Non-Controlling Interests - Spero Potentiator - Additional Information (Detail) - USD ($) | 1 Months Ended | ||||||
Jun. 30, 2017 | Aug. 31, 2016 | Jan. 31, 2016 | Nov. 30, 2015 | Feb. 28, 2015 | Sep. 30, 2018 | Dec. 31, 2017 | |
Noncontrolling Interest [Line Items] | |||||||
Non-controlling interest | $ 355,000 | $ 355,000 | |||||
Spero Potentiator, Inc. [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Common stock shares issued | 2,160 | 2,160 | 2,736 | ||||
Proceeds from the issuance of common stock, net of issuance costs | $ 0 | $ 0 | $ 0 | ||||
Non-controlling interest | $ 0 | ||||||
Spero Potentiator, Inc. [Member] | Anti- dilution Rights [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Fair value of derivative liability | $ 2,400,000 | ||||||
Spero Potentiator, Inc. [Member] | Northern Antibiotics Oy Ltd. [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Common stock shares issued | 996 | ||||||
Common stock issued, aggregate fair value | $ 1,100,000 | ||||||
Increase in non-controlling interest and reduction of derivative liability | $ 1,000,000 | $ 1,000,000 | $ 1,500,000 | ||||
Cash payment for repurchase of shares | $ 1,000,000 | ||||||
Contingent consideration | 100,000 | ||||||
Milestone payments | 7,000,000 | ||||||
Cash payment for repurchase of shares | 2,500,000 | ||||||
Non-controlling interest | 6,400,000 | ||||||
Increase to accumulated deficit | $ 1,000,000 | ||||||
Spero Potentiator, Inc. [Member] | Northern Antibiotics Oy Ltd. [Member] | Anti- dilution Rights [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Ownership percentage | 49.90% | ||||||
Proceeds from the issuance of common stock, net of issuance costs | $ 0 |
Non-Controlling Interests - S_2
Non-Controlling Interests - Spero Europe - Additional Information (Detail) - USD ($) | 1 Months Ended | 3 Months Ended | 9 Months Ended | ||||
Jan. 31, 2016 | Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017 | May 31, 2017 | |
Noncontrolling Interest [Line Items] | |||||||
Research and development expense | $ 8,459,000 | $ 6,910,000 | $ 24,758,000 | $ 20,366,000 | |||
Non-controlling interest | 355,000 | 355,000 | $ 355,000 | ||||
Spero Europe, Ltd. [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Termination of agreement notice period | 30 days | ||||||
Non-controlling interest | $ 0 | $ 0 | |||||
Spero Europe, Ltd. [Member] | Maximum [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Non-controlling interest | $ 100,000 | ||||||
Spero Europe, Ltd. [Member] | Licensing Agreements [Member] | Anti- dilution Rights [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Research and development expense | $ 200,000 | ||||||
Spero Europe, Ltd. [Member] | Promiliad Biopharma, Inc. [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Ownership percentage | 5.00% | ||||||
Common stock issued, aggregate fair value | $ 100,000 | ||||||
Milestone payments | 4,100,000 | ||||||
Proceeds from the issuance of common stock, net of issuance costs | 0 | ||||||
Maximum amounts of investments for anti-dilution protection | $ 5,000,000 | ||||||
Spero Europe, Ltd. [Member] | Promiliad Biopharma, Inc. [Member] | Anti- dilution Rights [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Ownership percentage | 5.00% | ||||||
Spero Europe, Ltd. [Member] | Promiliad Biopharma, Inc. [Member] | Licensing Agreements [Member] | |||||||
Noncontrolling Interest [Line Items] | |||||||
Research and development expense | $ 100,000 |
Non-Controlling Interests - S_3
Non-Controlling Interests - Spero Gyrase - Additional Information (Detail) - USD ($) | 1 Months Ended | 3 Months Ended | 9 Months Ended | ||
Mar. 31, 2016 | Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Noncontrolling Interest [Line Items] | |||||
Research and development expense | $ 8,459,000 | $ 6,910,000 | $ 24,758,000 | $ 20,366,000 | |
Spero Gyrase, Inc. [Member] | Anti- dilution Rights [Member] | Research and Development Expenses [Member] | |||||
Noncontrolling Interest [Line Items] | |||||
Fair value of derivative liability | $ 1,600,000 | ||||
Spero Gyrase, Inc. [Member] | Aviragen Therapeutics, Inc. [Member] | |||||
Noncontrolling Interest [Line Items] | |||||
Common stock shares issued | 200 | ||||
Common stock issued, aggregate fair value | $ 1,100,000 | ||||
Ownership percentage | 20.00% | ||||
Spero Gyrase, Inc. [Member] | Aviragen Therapeutics, Inc. [Member] | Anti- dilution Rights [Member] | |||||
Noncontrolling Interest [Line Items] | |||||
Ownership percentage | 20.00% | ||||
Proceeds from the issuance of common stock, net of issuance costs | $ 0 | ||||
Spero Gyrase, Inc. [Member] | Aviragen Therapeutics, Inc. [Member] | Anti- dilution Rights [Member] | Maximum [Member] | |||||
Noncontrolling Interest [Line Items] | |||||
Gross proceeds from equity financings | 8,000,000 | ||||
Spero Gyrase, Inc. [Member] | Aviragen Therapeutics, Inc. [Member] | Technology-Based Intangible Assets [Member] | |||||
Noncontrolling Interest [Line Items] | |||||
Research and development expense | $ 1,100,000 |
Non-Controlling Interests - S_4
Non-Controlling Interests - Spero Cantab - Additional Information (Detail) | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | 28 Months Ended | ||||
Dec. 31, 2017USD ($) | Jul. 31, 2017USD ($) | Jun. 30, 2016USD ($)Optionshares | Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) | Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) | Dec. 31, 2017USD ($) | Sep. 30, 2018USD ($)Option | |
Noncontrolling Interest [Line Items] | |||||||||
Research and development expense | $ 8,459,000 | $ 6,910,000 | $ 24,758,000 | $ 20,366,000 | |||||
Non-controlling interest | $ 355,000 | 355,000 | 355,000 | $ 355,000 | $ 355,000 | ||||
Spero Cantab [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Non-controlling interest | 0 | 0 | 0 | ||||||
Spero Cantab [Member] | Cantab Agreements [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Common stock shares issued | shares | 125 | ||||||||
Ownership percentage | 12.50% | ||||||||
Common stock issued, aggregate fair value | $ 1,600,000 | ||||||||
Upfront consideration | 300,000 | ||||||||
Non-controlling interest | 1,600,000 | ||||||||
Cash payment for repurchase of shares | $ 200,000 | ||||||||
Spero Cantab [Member] | Cantab Agreements [Member] | Contingent Milestone Payments [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Cash payment for repurchase of shares | $ 100,000 | ||||||||
Spero Cantab [Member] | Cantab Anti Infectives Ltd. [Member] | Cantab Agreements [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Research and development expense | 300,000 | ||||||||
Spero Cantab [Member] | Cantab Anti Infectives Ltd. [Member] | Cantab Agreements [Member] | Niaid [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Maximum potential funding from government contract | $ 6,300,000 | ||||||||
Number of option period for funding from government contract | Option | 3 | ||||||||
Maximum received fund | 1,300,000 | 1,300,000 | |||||||
Spero Cantab [Member] | Cantab Anti Infectives Ltd. [Member] | Cantab Agreements [Member] | Niaid [Member] | First Option [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Committed amount from government contract to date | $ 5,700,000 | ||||||||
Number of option period for funding from government contract committed to date | Option | 2 | ||||||||
Spero Cantab [Member] | New Pharma License Holding Limited [Member] | Cantab Agreements [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Research and development expense | $ 1,600,000 | ||||||||
Spero Cantab [Member] | Pro Bono Bio PLC [Member] | Cantab Agreements [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Maximum amounts of investments for anti-dilution protection | $ 8,000,000 | ||||||||
Spero Cantab [Member] | Pro Bono Bio PLC [Member] | Cantab Agreements [Member] | Minimum [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Ownership percentage | 5.00% | ||||||||
Spero Cantab [Member] | Pro Bono Bio PLC [Member] | Cantab Agreements [Member] | Maximum [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Ownership percentage | 12.50% | ||||||||
Spero Gyrase, Inc. [Member] | |||||||||
Noncontrolling Interest [Line Items] | |||||||||
Non-controlling interest | $ 400,000 | $ 400,000 | $ 400,000 | $ 400,000 | $ 400,000 |
Commitments and Contingencies -
Commitments and Contingencies - Additional Information (Detail) $ in Millions | Jan. 17, 2018USD ($)ft²Option | Jul. 31, 2016USD ($) | Aug. 31, 2015USD ($) | Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) | Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) |
Other Commitments [Line Items] | |||||||
Rent expense | $ 0.2 | $ 0.2 | $ 0.6 | $ 0.6 | |||
Office Space [Member] | |||||||
Other Commitments [Line Items] | |||||||
Operating lease beginning date | 2016-01 | ||||||
Operating lease expiration date | 2020-12 | ||||||
Annual lease payments | $ 0.4 | ||||||
Term of lease | 5 years | ||||||
Lease renewal term | 5 years | ||||||
Security deposit | $ 0.2 | ||||||
Annual rent escalations and tenant incentives | 0.7 | ||||||
Amount reimbursed | $ 0.3 | ||||||
Office Space [Member] | Lease Agreements [Member] | Cambridge, Massachusetts [Member] | U.S. REIF Central Plaza Massachusetts, LLC [Memebr] | |||||||
Other Commitments [Line Items] | |||||||
Term of lease | 7 years | ||||||
Lease renewal term | 5 years | ||||||
Lease expiration date | Dec. 1, 2018 | ||||||
Area of office space | ft² | 7,800 | ||||||
Number of renewal options | Option | 2 | ||||||
Operating lease, option to extend | the Company has two consecutive options to extend the Lease Term for an additional period of five years (the “Option Terms”), subject to certain conditions, upon notice to the Landlord. | ||||||
Operating leases annual base rent initial | $ 0.5 | ||||||
Operating leases annual base rent final | $ 0.6 | ||||||
Operating lease percentage of annual base rent | 100.00% | ||||||
Leasehold improvements receivable from the landlord | $ 0.4 | ||||||
Laboratory Space [Member] | |||||||
Other Commitments [Line Items] | |||||||
Annual lease payments | $ 0.3 | ||||||
Lease expiration date | Nov. 30, 2019 |
Commitments and Contingencies_2
Commitments and Contingencies - Summary of Future Minimum Payments Due Under Operating Leases (Detail) $ in Thousands | Sep. 30, 2018USD ($) |
Operating Leases Future Minimum Payments Due [Abstract] | |
2018 (remainder) | $ 248 |
2,019 | 1,323 |
2,020 | 1,016 |
2,021 | 957 |
2,022 | 1,076 |
Thereafter | 2,200 |
Total | $ 6,820 |
Government Contracts - Addition
Government Contracts - Additional Information (Detail) | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | 28 Months Ended | |||||||||
Jul. 31, 2018USD ($)Option | Feb. 28, 2018USD ($) | Dec. 31, 2017USD ($) | Apr. 30, 2017USD ($) | Feb. 28, 2017USD ($) | Sep. 30, 2016USD ($) | Jun. 30, 2016USD ($)Option | Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) | Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) | Dec. 31, 2017USD ($) | Sep. 30, 2018USD ($)Option | Mar. 12, 2018USD ($) | |
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | $ 658,000 | $ 597,000 | $ 2,274,000 | $ 986,000 | ||||||||||
BARDA [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Potential contract amount awarded | $ 44,200,000 | |||||||||||||
Option exercise | Option | 2 | |||||||||||||
BARDA [Member] | Base Period Contracts [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Potential amount initial funding awarded | $ 15,700,000 | |||||||||||||
Contract term | 3 years | |||||||||||||
BARDA [Member] | Grant [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | 200,000 | 200,000 | ||||||||||||
BARDA [Member] | First Option [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Potential grant amount awarded | $ 13,600,000 | |||||||||||||
BARDA [Member] | Second Option [member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Potential grant amount awarded | $ 14,900,000 | |||||||||||||
U.S. Department of Defense [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Contract term | 2 years | |||||||||||||
Potential grant amount awarded | $ 1,500,000 | |||||||||||||
U.S. Department of Defense [Member] | Grant [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | 100,000 | 200,000 | 400,000 | |||||||||||
U.S. Department of Defense [Member] | Grant [Member] | Maximum [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | 100,000 | |||||||||||||
Niaid [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Contract term | 12 months | |||||||||||||
Niaid [Member] | Spero Cantab [Member] | Cantab Anti Infectives Ltd. [Member] | Cantab Agreements [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Maximum potential funding from government contract | $ 6,300,000 | |||||||||||||
Number of option period for funding from government contract | Option | 3 | |||||||||||||
Maximum received fund | $ 1,300,000 | $ 1,300,000 | ||||||||||||
Niaid [Member] | Spero Cantab [Member] | Pro Bono Bio PLC [Member] | Cantab Agreements [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | 400,000 | 1,100,000 | ||||||||||||
Amount paid upfront as part of agreement | 300,000 | |||||||||||||
Niaid [Member] | Spero Cantab [Member] | Pro Bono Bio PLC [Member] | Cantab Agreements [Member] | Research and Development Expenses [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Expense associated with amounts payable under agreement | 100,000 | 400,000 | ||||||||||||
Niaid [Member] | Base Period Contracts [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Potential grant amount awarded | $ 600,000 | |||||||||||||
Niaid [Member] | Grant [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | 100,000 | 300,000 | 100,000 | |||||||||||
Niaid [Member] | Grant [Member] | Maximum [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | 100,000 | |||||||||||||
Niaid [Member] | Option Period Contracts [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Contract term | 12 months | |||||||||||||
Potential grant amount awarded | $ 400,000 | |||||||||||||
Potential grant amount exercised | $ 400,000 | |||||||||||||
Niaid [Member] | First Option [Member] | Spero Cantab [Member] | Cantab Anti Infectives Ltd. [Member] | Cantab Agreements [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Number of option period for funding from government contract | Option | 2 | |||||||||||||
Committed amount from government contract | $ 5,700,000 | |||||||||||||
CARB-X [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Contract term | 12 months | |||||||||||||
Potential grant amount awarded | $ 1,500,000 | |||||||||||||
Potential grant amount exercised | $ 0 | |||||||||||||
CARB-X [Member] | First Option [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Potential grant amount awarded | $ 400,000 | |||||||||||||
CARB-X [Member] | Grant [Member] | ||||||||||||||
Government Contracts [Line Items] | ||||||||||||||
Grant revenue | $ 0 | $ 400,000 | $ 500,000 | $ 500,000 |
Collaboration and License Agr_2
Collaboration and License Agreements - Additional Information (Detail) £ in Millions | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | ||||||
Nov. 30, 2017USD ($) | Jun. 30, 2017USD ($) | Jun. 30, 2016USD ($) | Jun. 30, 2016GBP (£) | May 31, 2016USD ($) | Mar. 31, 2016USD ($) | Dec. 31, 2018USD ($) | Sep. 30, 2018USD ($) | Dec. 31, 2017USD ($) | Oct. 31, 2017USD ($) | |
Aviragen Agreement [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Potential milestone payment upon achievement of specified clinical, regulatory and commercial milestones | $ 12,000,000 | |||||||||
Cantab Related Agreements [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Potential milestone payment upon achievement of specified clinical and regulatory milestones | $ 5,800,000 | |||||||||
Potential milestone payment upon achievement of specified commercial milestone | £ 5 | $ 6,500,000 | $ 6,700,000 | |||||||
Contract termination period | 10 years | 10 years | ||||||||
Vertex License Agreement [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Contract termination period | 10 years | |||||||||
Nonrefundable upfront payments | $ 500,000 | |||||||||
Potential milestone payment upon achievement of specified clinical, regulatory and commercial milestones | $ 81,100,000 | |||||||||
Contract termination period if no material development or commercialization occurs | 1 year | |||||||||
Meiji License Agreement [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Potential milestone payment upon achievement of specified clinical and regulatory milestones | $ 3,000,000 | |||||||||
Nonrefundable upfront payments | 600,000 | |||||||||
Potential milestone payments upon achievement of specified condition | $ 1,000,000 | |||||||||
Meiji License Agreement [Member] | Scenario Forecast [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
License agreement fixed assets related payments | $ 1,600,000 | |||||||||
Meiji License Agreement [Member] | Maximum [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Sublicense fee payable to counter party | 7,500,000 | |||||||||
Northern License Agreement [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Potential milestone payment upon achievement of specified clinical, regulatory and other milestones | 7,000,000 | |||||||||
Potential milestone payment upon closing of initial public offering | 2,500,000 | |||||||||
Northern Exchange Agreement [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Potential milestone payment upon closing of initial public offering | $ 100,000 | |||||||||
Northern License And Exchange Agreement [Member] | ||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | ||||||||||
Potential milestone payment upon closing of initial public offering | $ 2,600,000 |
Australia Research and Develo_2
Australia Research and Development Tax Incentive - Additional Information (Detail) - Spero Potentiator Australia Pty Limited [Member] - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | |||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017 | |
Australia [Member] | |||||
Schedule Of Income Tax [Line Items] | |||||
Tax incentive receivable | $ 0.7 | $ 0.7 | $ 1.9 | ||
Research and Development Expenses [Member] | |||||
Schedule Of Income Tax [Line Items] | |||||
Percentage of refundable tax incentive | 43.50% | ||||
Reduction to research and development expenses | $ 0.3 | $ 0.1 | $ 0.7 | $ 0.8 |
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 | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Numerator: | ||||
Net loss | $ (10,463) | $ (9,844) | $ (31,063) | $ (26,018) |
Less: Net loss attributable to non-controlling interests | (8) | (1,137) | ||
Plus: Cumulative dividends on redeemable convertible preferred shares | (2,052) | (5,313) | ||
Plus: Accretion of bridge units and redeemable convertible preferred shares to redemption value | (188) | (1,133) | ||
Net loss attributable to common stockholders of Spero Therapeutics, Inc. | $ (10,463) | $ (12,076) | $ (31,063) | $ (31,327) |
Denominator: | ||||
Weighted average common shares outstanding, basic and diluted | 17,471,462 | 335,285 | 15,417,087 | 333,402 |
Net loss per share attributable to common stockholders of Spero Therapeutics, Inc., basic and diluted | $ (0.60) | $ (36.02) | $ (2.01) | $ (93.96) |
Net Loss per Share - Summary _2
Net Loss per Share - Summary of Shares Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares | 3 Months Ended | 9 Months Ended | ||
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 4,406,378 | 9,603,877 | 4,406,378 | 9,603,877 |
Options to Purchase Common Stock [Member] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 2,186,378 | 1,541,474 | 2,186,378 | 1,541,474 |
Series A Convertible Preferred Stock [Member] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 2,220,000 | 2,220,000 | ||
Redeemable Convertible Preferred Shares [Member] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 8,062,403 | 8,062,403 |