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NTLA Intellia Therapeutics

Document and Entity Information

Document and Entity Information - shares3 Months Ended
Mar. 31, 2021Apr. 30, 2021
Cover [Abstract]
Document Type10-Q
Amendment Flagfalse
Document Period End DateMar. 31,
2021
Document Fiscal Year Focus2021
Document Fiscal Period FocusQ1
Trading SymbolNTLA
Entity Registrant NameINTELLIA THERAPEUTICS, INC.
Entity Central Index Key0001652130
Current Fiscal Year End Date--12-31
Entity Filer CategoryLarge Accelerated Filer
Entity Small Businessfalse
Entity Emerging Growth Companyfalse
Entity Common Stock, Shares Outstanding68,153,597
Entity Current Reporting StatusYes
Entity Interactive Data CurrentYes
Entity Shell Companyfalse
Entity File Number001-37766
Entity Tax Identification Number36-4785571
Entity Address, Address Line One40 Erie Street
Entity Address, Address Line TwoSuite 130
Entity Address, City or TownCambridge
Entity Address, State or ProvinceMA
Entity Address, Postal Zip Code02139
City Area Code857
Local Phone Number285-6200
Entity Incorporation, State or Country CodeDE
Title of 12(b) SecurityCommon Stock, par value $0.0001 per share
Security Exchange NameNASDAQ
Document Quarterly Reporttrue
Document Transition Reportfalse

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Current Assets:
Cash and cash equivalents $ 141,538 $ 160,020
Marketable securities442,525 437,351
Accounts receivable953 2,130
Prepaid expenses and other current assets16,068 17,016
Total current assets601,084 616,517
Marketable securities - noncurrent16,735
Property and equipment, net16,157 15,943
Operating lease right-of-use assets77,912 39,114
Other assets5,003 4,748
Total Assets716,891 676,322
Current Liabilities:
Accounts payable8,688 10,460
Accrued expenses21,215 25,554
Current portion of operating lease liability8,255 5,696
Current portion of deferred revenue22,544 22,544
Total current liabilities60,702 64,254
Deferred revenue, net of current portion45,829 51,387
Long-term operating lease liability64,487 33,609
Commitments and contingencies (Note 6)
Stockholders’ Equity:
Common stock, $0.0001 par value; 120,000,000 shares authorized; 67,890,334 and 66,234,056 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively7 7
Additional paid-in capital1,027,192 962,173
Accumulated other comprehensive (loss) income(12)1
Accumulated deficit(481,314)(435,109)
Total stockholders’ equity545,873 527,072
Total Liabilities and Stockholders’ Equity $ 716,891 $ 676,322

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / sharesMar. 31, 2021Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value $ 0.0001 $ 0.0001
Common stock, shares authorized120,000,000 120,000,000
Common stock, shares issued67,890,334 66,234,056
Common stock, shares outstanding67,890,334 66,234,056

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Income Statement [Abstract]
Collaboration revenue $ 6,445 $ 12,916
Type of Revenue [Extensible List]us-gaap:LicenseAndServiceMemberus-gaap:LicenseAndServiceMember
Operating expenses:
Research and development $ 39,276 $ 34,650
General and administrative13,594 11,314
Total operating expenses52,870 45,964
Operating loss(46,425)(33,048)
Interest income220 1,242
Net loss $ (46,205) $ (31,806)
Net loss per share, basic and diluted $ (0.69) $ (0.63)
Weighted average shares outstanding, basic and diluted67,183 50,491
Other comprehensive (loss) income:
Unrealized (loss) gain on marketable securities $ (13) $ 112
Comprehensive loss $ (46,218) $ (31,694)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands3 Months Ended71 Months Ended
Mar. 31, 2021Mar. 31, 2020Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss $ (46,205) $ (31,806)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization1,591 1,541
Equity-based compensation6,424 4,157
Amortization/accretion of investment premiums/discounts1,209 (200)
Changes in operating assets and liabilities:
Accounts receivable1,177 (8,748)
Prepaid expenses and other current assets(5,448)(448)
Operating right-of-use assets1,596 1,566
Other assets(255)97
Accounts payable(917)(370)
Accrued expenses(4,588)177
Deferred revenue(5,558)(3,151)
Operating lease liabilities(1,402)(1,360)
Net cash used in operating activities(52,376)(38,545)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment(2,412)(845)
Purchases of marketable securities(148,330)(31,207)
Maturities of marketable securities125,200 89,500
Net cash (used in) provided by investing activities(25,542)57,448
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock through at-the-market offerings, net of issuance costs $ 1,165,300
Proceeds from options exercised13,340 336
Net cash provided by financing activities58,595 4,864
Net (decrease) increase in cash and cash equivalents and restricted cash and cash equivalents(19,323)23,767
Cash and cash equivalents and restricted cash and cash equivalents, beginning of period164,606 57,226
Cash and cash equivalents and restricted cash and cash equivalents, end of period145,283 80,993 145,283
Reconciliation of cash and cash equivalents and restricted cash and cash equivalents to condensed consolidated balance sheet:
Cash and cash equivalents141,538 80,993 141,538
Restricted cash and cash equivalents, included in prepaids and other current assets and other assets3,745 3,745
Cash and cash equivalents and restricted cash and cash equivalents, end of period145,283 80,993 145,283
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Purchases of property and equipment unpaid at period end901 750
Right-of-use assets acquired under operating leases40,394 7,347
Proceeds from at-the-market offerings unpaid at period end551
At The Market Offerings [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock through at-the-market offerings, net of issuance costs $ 45,255 $ 4,528 $ 196,500

Overview and Basis of Presentat

Overview and Basis of Presentation3 Months Ended
Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Overview and Basis of Presentation1.
Overview and Basis of Presentation Intellia Therapeutics, Inc. (“Intellia” or the “Company”) is a leading clinical-stage genome editing company, focused on developing proprietary, potentially curative CRISPR/Cas9-based therapeutics. CRISPR/Cas9, an acronym for C lustered, R egularly I nterspaced S hort P alindromic R epeats (“CRISPR”)/CRISPR associated 9 (“Cas9”), is a technology for genome editing, the process of altering selected sequences of genomic deoxyribonucleic acid (“DNA”). transform medicine by both producing therapeutics that permanently edit and/or correct disease-associated genes in the human body with a single dose of treatment and creating enhanced engineered cell therapies. The Company’s combination of deep scientific, technical and clinical development experience, and proprietary innovations in genome editing and delivery technologies, along with its intellectual property (“IP”) portfolio, puts it in a position to unlock broad therapeutic applications of the CRISPR/Cas9 technology and create new classes of therapeutic products. The condensed consolidated financial statements of the Company included herein have been prepared, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K (“Annual Report”) for the year ended December 31, 2020. The unaudited condensed consolidated financial statements include the accounts of Intellia Therapeutics, Inc. and its wholly owned, controlled subsidiary, Intellia Securities Corp. All intercompany balances and transactions have been eliminated in consolidation. Comprehensive loss is comprised of net loss and unrealized gain/loss on marketable securities. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates, judgments and assumptions that affect the amounts reported in the financial statements and accompanying notes. Significant estimates in these condensed consolidated financial statements have been made in connection with the calculation of revenues, research and development expenses and equity-based compensation expense. The Company bases its estimates on historical experience and various other assumptions that management believes to be reasonable under the circumstances at the time such estimates are made. Actual results could differ from those estimates. The Company periodically reviews its estimates in light of changes in circumstances, facts and experience. The extent of the impact of the coronavirus disease 19 (“COVID-19”) pandemic on the Company’s operational and financial performance will depend on certain developments, including the length and severity of this pandemic, as well as its effect on our employees, collaborators and vendors, all of which are uncertain and cannot be predicted. The Company cannot reasonably estimate the extent to which the disruption may materially impact its consolidated results of operations or financial position. The effects of material revisions in estimates are reflected in the condensed consolidated financial statements prospectively from the date of the change in estimate. In the opinion of management, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair presentation of the results for the reported interim periods. The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period. Liquidity Since its inception through March 31, 2021, the Company has raised an aggregate of $1,165.3 million to fund its operations, of which $275.0 million was through its collaboration agreements, $170.5 million was from its initial public offering (“IPO”) and concurrent private placements, $438.3 million was from follow-on public offerings, $196.5 million was from at-the-market offerings and $85.0 million was from the sale of convertible preferred stock. The Company expects that its cash, cash equivalents and marketable securities as of March 31, 2021, as well as research and cost reimbursement funding from its collaboration agreement with Regeneron Pharmaceuticals, Inc. (“Regeneron”) (see Note 7), will enable the Company to fund its ongoing operating expenses and capital expenditure requirements for at least the twelve-month period following the issuance of these condensed consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies3 Months Ended
Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies2.
Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies” to the consolidated financial statements included in the Annual Report for the year ended December 31, 2020. There have been no material changes during the three months ended March 31, 2021, other than as noted below Recent Accounting Pronouncements – Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The Company adopted ASU 2019-12 on January 1, 2021. The adoption did not have a material effect on the Company’s condensed consolidated financial statements.

Marketable Securities

Marketable Securities3 Months Ended
Mar. 31, 2021
Investments Debt And Equity Securities [Abstract]
Marketable Securities3.
Marketable Securities The following table summarizes the Company’s available-for-sale marketable securities as of March 31, 2021 and December 31, 2020 at net book value:
March 31, 2021
Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Estimated Fair Value
(In thousands)
Marketable securities:
U.S. Treasury and other government securities
$
204,473
$
49
$
(4
)
$
204,518
Financial institution debt securities
169,979
7
(45
)
169,941
Corporate debt securities
51,311
1
(13
)
51,299
Other asset-backed securities
33,509
1
(8
)
33,502
Total
$
459,272
$
58
$
(70
)
$
459,260
December 31, 2020
Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Estimated Fair Value
(In thousands)
Marketable securities:
U.S. Treasury and other government securities
$
245,666
$
13
$
(11
)
$
245,668
Financial institution debt securities
138,445
6
(8
)
138,443
Corporate debt securities
41,765
3
(2
)
41,766
Other asset-backed securities
11,474
1
(1
)
11,474
Total
$
437,350
$
23
$
(22
)
$
437,351
The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At March 31, 2021 and December 31, 2020, the balance in the Company’s accumulated other comprehensive (loss) income was composed of activity related to the Company’s available-for-sale marketable securities. There were no realized gains or losses in the three months ended March 31, 2021 or for the year ended December 31, 2020. The Company did not reclassify any amounts out of accumulated other comprehensive (loss) income during this period. The Company did not have any securities in a material unrealized loss position at March 31, 2021 or December 31, 2020. The Company's available-for-sale securities that are classified as short-term marketable securities in the condensed consolidated balance sheet mature within one year or less as of the balance sheet date. Available-for-sale securities that are classified as noncurrent in the condensed consolidated balance sheet are those that mature after one year but within five years from the balance sheet date and that the Company does not intend to dispose of within the next twelve months. At March 31, 2021 and December 31, 2020, the Company did not hold any investments that matured beyond five years of the balance sheet date.

Fair Value Measurements

Fair Value Measurements3 Months Ended
Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements4 .
Fair Value Measurements The Company classifies fair value-based measurements using a three-level hierarchy that prioritizes the inputs used to measure fair value. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1, quoted market prices in active markets for identical assets or liabilities; Level 2, observable inputs other than quoted market prices included in Level 1, such as quoted market prices for markets that are not active or other inputs that are observable or can be corroborated by observable market data; and Level 3, unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities, including certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. As of March 31, 2021 and December 31, 2020, the Company’s financial assets recognized at fair value on a recurring basis consisted of the following:
Fair Value as of March 31, 2021
Total
Level 1
Level 2
Level 3
(In thousands)
Cash equivalents and restricted cash equivalents
$
143,129
$
143,129
$
-
$
-
Marketable securities:
U.S. Treasury and other government securities
204,518
181,118
23,400
-
Financial institution debt securities
169,941
-
169,941
-
Corporate debt securities
51,299
-
51,299
-
Other asset-backed securities
33,502
-
33,502
-
Total marketable securities
459,260
181,118
278,142
-
Total
$
602,389
$
324,247
$
278,142
$
-
Fair Value as of December 31, 2020
Total
Level 1
Level 2
Level 3
(In thousands)
Cash equivalents and restricted cash equivalents
$
163,805
$
163,805
$
-
$
-
Marketable securities:
U.S. Treasury and other government securities
245,668
241,664
4,004
-
Financial institution debt securities
138,443
-
138,443
-
Corporate debt securities
41,766
-
41,766
-
Other asset-backed securities
11,474
-
11,474
-
Total marketable securities
437,351
241,664
195,687
-
Total
$
601,156
$
405,469
$
195,687
$
-
Certain of the Company’s financial assets, including cash equivalents, restricted cash equivalents and marketable securities, have been initially valued at the transaction price, and subsequently revalued at the end of each reporting period, utilizing third-party pricing services or other observable market data. The pricing services utilize industry standard valuation models and observable market inputs to determine value . After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by the pricing services as of March 31, 2021 or December Other financial instruments, including accounts receivable, accounts payable and accrued expense, are carried at cost, which approximates fair value due to the short duration and term to maturity.

Accrued Expenses

Accrued Expenses3 Months Ended
Mar. 31, 2021
Payables And Accruals [Abstract]
Accrued Expenses5 .
Accrued Expenses Accrued expenses consisted of the following:
March 31,
December 31,
2021
2020
(In thousands)
Accrued research and development
$
10,010
$
11,008
Employee compensation and benefits
6,244
10,920
Accrued legal and professional expenses
2,833
1,876
Accrued other
2,128
1,750
Total accrued expenses
$
21,215
$
25,554

Commitments and Contingencies

Commitments and Contingencies3 Months Ended
Mar. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies6.
Commitments and Contingencies Litigation There have been no material changes Caribou Arbitration On October 17, 2018, the Company initiated an arbitration proceeding against Caribou Biosciences, Inc. (“Caribou”) asserting that Caribou violated the terms and conditions of a license agreement the Company entered into with them in July 2014 related to certain IP (the “Caribou License”), as well as other contractual and legal obligations to the Company, by using and seeking to license to third parties two patent families relating to specific structural or chemical modifications of guide RNAs (“gRNAs”), that were purportedly invented or controlled by Caribou, in the Company’s exclusive human therapeutic field, before an agreed-upon cutoff date of January 30, 2018. On September 26, 2019, the Company announced that the arbitration panel issued an interim award concluding that both the structural and chemical gRNA modification technologies were exclusively licensed to the Company by Caribou pursuant to the Caribou License. Nevertheless, the arbitration panel, solely with respect to the clinically modified gRNAs, stated that it will declare that Caribou has an equitable “leaseback”, which it described as exclusive, perpetual and worldwide (the “Caribou Award”). The Caribou Award does not include the structural guide modifications IP also at issue in the arbitration, any other IP exclusively licensed or sublicensed by Caribou to the Company under the Caribou License (including but not limited to the foundational CRISPR/Cas9 IP co-owned by the Regents of the University of California, University of Vienna and Dr. Emmanuelle Charpentier), or any other of the Company’s IP. On February 6, 2020, the panel clarified that the Caribou Award is limited to a particular on-going Caribou program, which seeks to develop a chimeric antigen receptor T (“CAR-T”) product directed at CD19. As instructed by the panel, the parties have been negotiating the terms of the Caribou Award, including Caribou’s future payments to the Company. License Agreements The Company is party to license agreements, which include contingent payments. These payments will become payable if and when certain development, regulatory and commercial milestones are achieved. As of March 31, 2021, the satisfaction and timing of the contingent payments is uncertain and not reasonably estimable .

Collaborations

Collaborations3 Months Ended
Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborations7 .
Collaborations To accelerate the development and commercialization of CRISPR/Cas9-based products in multiple therapeutic areas, the Company has formed, and intends to seek other opportunities to form, strategic alliances with collaborators who can augment its leadership in CRISPR/Cas9 therapeutic development. As of March 31, 2021, the Company’s accounts receivable and contract liabilities were related to the Company’s collaboration with Regeneron. As of March 31, 2020, the Company’s accounts receivable and contract liabilities were related to the Company’s collaborations with Regeneron and Novartis Institutes for BioMedical Research (“Novartis”). The following table presents changes in the Company’s accounts receivable and contract liabilities during the three months ended March 31, 2021 and 2020 (in thousands):
Balance at Beginning of Period
Additions
Deductions
Balance at End of Period
Three Months Ended March 31, 2021
Accounts receivable
$
2,130
$
953
$
(2,130
)
$
953
Contract liabilities:
Deferred revenue
$
73,931
$
-
$
(5,558
)
$
68,373
Balance at Beginning of Period
Additions
Deductions
Balance at End of Period
Three Months Ended March 31, 2020
Accounts receivable
$
4,620
$
9,765
$
(1,017
)
$
13,368
Contract liabilities:
Deferred revenue
$
28,810
$
-
$
(3,151
)
$
25,659
During the three months ended March 31, 2021 and 2020, the Company recognized the following revenues as a result of changes in the contract liability balance (in thousands):
Three Months Ended March 31,
Revenue recognized in the period from:
2021
2020
Amounts included in the contract liability at the beginning of the period
$
5,558
$
3,151
Costs to obtain and fulfill a contract The Company did not incur any expenses to obtain collaboration agreements and costs to fulfill those contracts do not generate or enhance resources of the Company. As such, no costs to obtain or fulfill a contract have been capitalized in any period. Regeneron Pharmaceuticals, Inc. License and Collaboration Agreement In April 2016, the Company entered into a license and collaboration agreement with Regeneron (the “2016 Regeneron Agreement”). The 2016 Regeneron Agreement has two principal components: (i) a product development component under which the parties will research, develop and commercialize CRISPR/Cas-based therapeutic products primarily focused on genome editing in the liver, and (ii) a technology collaboration component, pursuant to which the Company and Regeneron will engage in research-related activities aimed at discovering and developing novel technologies and improvements to CRISPR/Cas technology to enhance the Company’s genome editing platform. Under this agreement, the Company also may access the Regeneron Genetics Center and proprietary mouse models to be provided by Regeneron for a limited number of the Company’s liver programs. On May 30, 2020, the Company entered into (i) amendment no. 1 (the “2020 Regeneron Amendment”) to the 2016 Regeneron Agreement, (ii) co-development and co-funding agreements for the treatment of hemophilia A and hemophilia B (the “Hemophilia Co/Co”) agreements and (iii) a stock purchase agreement. The collaboration expansion builds upon the jointly developed targeted transgene insertion capabilities designed to durably restore missing therapeutic protein, and to overcome the limitations of traditional gene therapy. The collaboration was extended until April 2024, at which point Regeneron has an option to renew for an additional two years. The 2020 Regeneron Amendment also grants Regeneron exclusive rights to develop products for five additional in vivo CRISPR/Cas-based therapeutic liver targets and non-exclusive rights to independently develop and commercialize up to 10 ex vivo gene edited products made using certain defined cell types. Since December 31, 2020, there have been no material changes to the key terms of the 2016 Regeneron Agreement and the 2020 Regeneron Amendment (the “Amended Agreements”). For further information on the terms and conditions of these agreements, please see the notes to the consolidated financial statements included in the Company’s Annual Report for the year ended December 31, 2020. Revenue Recognition – Collaboration Revenue. Through March 31, 2021, excluding amounts allocated to Regeneron’s purchase of the Company’s common stock, the Company recorded $145.0 million in upfront payments under the Amended Agreements and $35.6 million primarily for research and development services under the ATTR Co/Co agreement. Through March 31, 2021, the Company has recognized $129.7 million of collaboration revenue under all arrangements, including $6.4 million and $7.9 million during the three months ended March 31, 2021 and 2020, respectively, in the condensed consolidated statements of operations and comprehensive loss. This includes $0.9 million and $4.8 million during the three months ended March 31, 2021 and 2020, respectively, primarily representing payments due from Regeneron pursuant to the ATTR Co/Co agreement. As of March 31, 2021, there was approximately $68.4 million of the aggregate transaction price of the Amended Agreements remaining to be recognized, which the Company expects to be recognized during the research term through April 2024. As of March 31, 2021 and December 31, 2020, the Company had accounts receivable of $1.0 million and $2.1 million, respectively, and deferred revenue of $68.4 million and $73.9 million, respectively, related to the Amended Agreements. Novartis Institutes for BioMedical Research, Inc. In December 2014, the Company entered into a strategic collaboration agreement with Novartis (the “2014 Novartis Agreement”), primarily focused on the research of new ex vivo Revenue Recognition – Milestone . During the three months ended March 31, 2020, the U.S. Food and Drug Administration (“FDA”) accepted the investigational new drug (“IND”) application submitted by Novartis for a CRISPR/Cas9-based engineered cell therapy for the treatment of sickle cell disease. As a result of meeting this milestone, the Company recognized $5.0 million as collaboration revenue within the condensed consolidated statement of operations and comprehensive loss. No other milestones under the 2014 Novartis Agreement and the Novartis Amendment were achieved during the three months ended March 31, 2021 or 2020. The Company is eligible to receive additional downstream success-based milestones and royalties. As of March 31, 2021 and December 31, 2020, the Company had no accounts receivable or deferred revenue related to the 2014 Novartis Agreement and the Novartis Amendment.

Leases

Leases3 Months Ended
Mar. 31, 2021
Leases [Abstract]
Leases8 .
Leases In March 2020, the Company entered into an agreement to lease approximately 39,000 square feet of office and laboratory space at 281 Albany Street in Cambridge, Massachusetts under an operating lease agreement (the “281 Albany Lease”). The Company’s obligation to pay rent will start on the date that is six months after the commencement date or the date on which the Company occupies the premises, whichever occurs earlier (the “Rent Commencement Date”). The initial term of the 281 Albany Lease is ten years following the Rent Commencement Date. As of March 31, 2021 the Company determined, in accordance with Accounting Standards Codification 842, “Leases (Topic 842)” 40.4 term of the lease. These restricted cash equivalents are reported in “Other Assets” in the Company’s condensed consolidated balance sheet. The Company has the option to extend the 281 Albany Lease for two successive five-year terms . The option for this extension is not included as part of the lease liability and right-of-use asset at March 31, 2021, as it is not reasonably certain that it will be exercised.

Equity-Based Compensation

Equity-Based Compensation3 Months Ended
Mar. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-Based Compensation9.
Equity-Based Compensation In April 2016, the Company adopted the Amended and Restated 2015 Stock Option and Incentive Plan (the “2015 Plan”). The 2015 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units (“RSUs”) and other stock-based awards. Recipients of incentive stock options and non-qualified stock options are eligible to purchase shares of the Company’s common stock at an exercise price equal to the fair value of such stock on the grant date. Stock options granted under the 2015 Plan generally vest 25% on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years, unless they contain specific performance-based vesting provisions. The maximum term of stock options granted under the 2015 Plan is ten years. As of March 31, 2021, there were 2,890,540 shares available for future issuance. The number of shares reserved for issuance under the 2015 Plan shall be cumulatively increased by four percent of the number of shares of stock issued and outstanding on the immediately preceding December 31 or such lesser number of shares of stock as determined by the board of directors. Equity-based compensation expense is classified in the condensed consolidated statements of operations and comprehensive loss as follows:
Three Months Ended March 31,
2021
2020
(In thousands)
Research and development
$
3,491
$
2,160
General and administrative
2,933
1,997
Total
$
6,424
$
4,157
Restricted Stock Restricted stock is measured at fair value based on the quoted price of the Company’s common stock. The following table summarizes the Company’s restricted stock activity for the three months ended March 31, 2021:
Number of Shares
Weighted Average Grant Date Fair Value per Share
Unvested restricted stock as of December 31, 2020
193,936
$
23.98
Granted
259,839
57.71
Vested
-
-
Cancelled
(11,035
)
27.59
Unvested restricted stock as of March 31, 2021
442,740
$
43.69
In March 2021, the Company granted 259,839 RSUs with a service condition to executive and non-executive employees as part of their annual grant, which vest over a period of four years. The weighted average grant date fair value of these RSUs was $57.71. The vesting start date for these RSUs is January 1, 2021. Included in the unvested restricted stock as of March 31, 2021 are 107,360 RSUs that include a performance condition in addition to a service condition. The RSUs vest over a period of three years and are subject to accelerated vesting based on the Company’s programs achieving certain development milestones before December 1, 2022. The fair value of the RSUs at date of grant was $15.05. There has been no additional vesting of these shares in the three months ended March 31, 2021. As of March 31, 2021, there was $17.8 Stock Options The weighted average grant date fair value of options, estimated as of the grant date using the Black-Scholes option pricing model, was $36.64 7.96 0.3
Three Months Ended March 31,
2021
2020
Risk-free interest rate
0.9%
1.0%
Expected life of options
6.0 years
6.0 years
Expected volatility of underlying stock
72.0%
66.7%
Expected dividend yield
0.0%
0.0%
Risk-free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant with maturities approximately equal to the option’s expected term. Expected Dividend Yield. The expected dividend yield assumption is based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends. Expected Volatility. The expected volatility was derived from a blend of the Company’s historical volatility and an average of the historical stock volatilities of several peer companies within the Company’s industry, both over a period equivalent to the expected term of the stock option grants. Expected Term. The expected term represents the period that stock option awards are expected to be outstanding. For option grants that are considered to be “plain vanilla,” the Company determines the expected term using the simplified method. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the options. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate the expected term. The Company uses the market closing price of its common stock as reported on the Nasdaq Global Select Market to determine the fair value of the shares of common stock underlying stock options. The following is a summary of stock option activity for the three months ended March 3 1 , 20 2 1 :
Number of Options
Weighted Average Exercise Price per Share
Weighted Average Remaining Contractual Term
Aggregate Intrinsic Value
(In years)
(In thousands)
Outstanding at December 31, 2020
6,977,440
$
15.43
Granted
1,645,823
57.94
Exercised
(1,014,569
)
13.15
Forfeited
(129,393
)
20.71
Outstanding at March 31, 2021
7,479,301
$
25.00
8.25
$
413,258
Exercisable at March 31, 2021
2,734,966
As of March 31, 2021, there was $86.9

Loss Per Share

Loss Per Share3 Months Ended
Mar. 31, 2021
Earnings Per Share [Abstract]
Loss Per Share10 .
Loss Per Share The Company calculates basic loss per share by dividing net loss for each respective period by the weighted average number of common shares outstanding for each respective period. The Company computes diluted loss per share after giving consideration to the dilutive effect of stock options and unvested restricted stock that are outstanding during the period, except where such securities would be anti-dilutive. Basic and diluted loss per share was calculated as follows:
Three Months Ended March 31,
2021
2020
(In thousands)
Net loss
$
(46,205
)
$
(31,806
)
Weighted average shares outstanding, basic and diluted
67,183
50,491
Net loss per share, basic and diluted
$
(0.69
)
$
(0.63
) The following common stock equivalents were excluded from the calculation of diluted loss per share because their inclusion would have been anti-dilutive:
Three Months Ended March 31,
2021
2020
(In thousands)
Unvested restricted stock
443
248
Stock options
7,479
7,243
7,922
7,491

Stockholders_ Equity

Stockholders’ Equity3 Months Ended
Mar. 31, 2021
Equity [Abstract]
Stockholders’ Equity11 .
Stockholders’ Equity The following tables present changes in stockholders’ equity for the three-month periods ended March 31, 2021 and 2020 (in thousands, except share data):
Additional
Accumulated Other
Total
Common
Paid-In
Comprehensive
Accumulated
Stockholders’
Shares
Amount
Capital
Income (Loss)
Deficit
Equity
Balance at December 31, 2020
66,234,056
$
7
$
962,173
$
1
$
(435,109
)
$
527,072
Issuance of common stock through at-the-market offerings, net of issuance costs of $52
641,709
-
45,255
-
-
45,255
Exercise of stock options
1,014,569
-
13,340
-
-
13,340
Equity-based compensation
-
-
6,424
-
-
6,424
Other comprehensive loss
-
-
-
(13
)
-
(13
)
Net loss
-
-
-
-
(46,205
)
(46,205
)
Balance at March 31, 2021
67,890,334
$
7
$
1,027,192
$
(12
)
$
(481,314
)
$
545,873
Additional
Accumulated Other
Total
Common
Paid-In
Comprehensive
Accumulated
Stockholders’
Shares
Amount
Capital
Income
Deficit
Equity
Balance at December 31, 2019
50,198,044
$
5
$
570,493
$
261
$
(300,878
)
$
269,881
Issuance of common stock through at-the-market offerings, net of issuance costs of $48
351,252
-
5,079
-
-
5,079
Exercise of stock options
53,579
-
336
-
-
336
Equity-based compensation
-
-
4,157
-
-
4,157
Other comprehensive income
-
-
-
112
-
112
Net loss
-
-
-
-
(31,806
)
(31,806
)
Balance at March 31, 2020
50,602,875
$
5
$
580,065
$
373
$
(332,684
)
$
247,759
At-the-Market Offering Programs I n August 2019, the Company entered into an Open Market Sale Agreement (the “2019 Sales Agreement”) with Jefferies, under which Jefferies was able to offer and sell, from time to time in “at-the-market” offerings, common stock having aggregate gross proceeds of up to $150.0 million. The Company agreed to pay Jefferies cash commissions of 3.0% of the gross proceeds of sales of common stock under the 2019 Sales Agreement. During the three months ended March 31, 2021, the Company issued 641,709 shares of its common stock in a series of sales at an average price of $72.79 per 45.3 approximately million related to legal, accounting and other fees in connection with the sales. $15.05 per 5.1 approximately $0.1 million related to legal, accounting and other fees in connection with the sales. As of March 31, 2021, $47.4 million in shares of common stock remain eligible for sale under the 2019 Sales

Related Party Transactions

Related Party Transactions3 Months Ended
Mar. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions1 2 .
Related Party Transactions In the ordinary course of business, the Company may purchase materials or supplies from entities that are associated with a party that meets the criteria of a related party of the Company. These transactions are reviewed quarterly and to date have not been material to the Company’s condensed consolidated financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)3 Months Ended
Mar. 31, 2021
Accounting Policies [Abstract]
Recent Accounting Pronouncements - AdoptedRecent Accounting Pronouncements – Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The Company adopted ASU 2019-12 on January 1, 2021. The adoption did not have a material effect on the Company’s condensed consolidated financial statements.

Marketable Securities (Tables)

Marketable Securities (Tables)3 Months Ended
Mar. 31, 2021
Investments Debt And Equity Securities [Abstract]
Summary of Available-for-sale Marketable SecuritiesThe following table summarizes the Company’s available-for-sale marketable securities as of March 31, 2021 and December 31, 2020 at net book value:
March 31, 2021
Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Estimated Fair Value
(In thousands)
Marketable securities:
U.S. Treasury and other government securities
$
204,473
$
49
$
(4
)
$
204,518
Financial institution debt securities
169,979
7
(45
)
169,941
Corporate debt securities
51,311
1
(13
)
51,299
Other asset-backed securities
33,509
1
(8
)
33,502
Total
$
459,272
$
58
$
(70
)
$
459,260
December 31, 2020
Amortized Cost
Gross Unrealized Gains
Gross Unrealized Losses
Estimated Fair Value
(In thousands)
Marketable securities:
U.S. Treasury and other government securities
$
245,666
$
13
$
(11
)
$
245,668
Financial institution debt securities
138,445
6
(8
)
138,443
Corporate debt securities
41,765
3
(2
)
41,766
Other asset-backed securities
11,474
1
(1
)
11,474
Total
$
437,350
$
23
$
(22
)
$
437,351

Fair Value Measurements (Tables

Fair Value Measurements (Tables)3 Months Ended
Mar. 31, 2021
Fair Value Disclosures [Abstract]
Summary of Financial Assets Recognized at Fair Value on Recurring BasisAs of March 31, 2021 and December 31, 2020, the Company’s financial assets recognized at fair value on a recurring basis consisted of the following:
Fair Value as of March 31, 2021
Total
Level 1
Level 2
Level 3
(In thousands)
Cash equivalents and restricted cash equivalents
$
143,129
$
143,129
$
-
$
-
Marketable securities:
U.S. Treasury and other government securities
204,518
181,118
23,400
-
Financial institution debt securities
169,941
-
169,941
-
Corporate debt securities
51,299
-
51,299
-
Other asset-backed securities
33,502
-
33,502
-
Total marketable securities
459,260
181,118
278,142
-
Total
$
602,389
$
324,247
$
278,142
$
-
Fair Value as of December 31, 2020
Total
Level 1
Level 2
Level 3
(In thousands)
Cash equivalents and restricted cash equivalents
$
163,805
$
163,805
$
-
$
-
Marketable securities:
U.S. Treasury and other government securities
245,668
241,664
4,004
-
Financial institution debt securities
138,443
-
138,443
-
Corporate debt securities
41,766
-
41,766
-
Other asset-backed securities
11,474
-
11,474
-
Total marketable securities
437,351
241,664
195,687
-
Total
$
601,156
$
405,469
$
195,687
$
-

Accrued Expenses (Tables)

Accrued Expenses (Tables)3 Months Ended
Mar. 31, 2021
Payables And Accruals [Abstract]
Schedule of Accrued ExpensesAccrued expenses consisted of the following:
March 31,
December 31,
2021
2020
(In thousands)
Accrued research and development
$
10,010
$
11,008
Employee compensation and benefits
6,244
10,920
Accrued legal and professional expenses
2,833
1,876
Accrued other
2,128
1,750
Total accrued expenses
$
21,215
$
25,554

Collaborations (Tables)

Collaborations (Tables)3 Months Ended
Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Changes in Accounts Receivable and Contract LiabilitiesThe following table presents changes in the Company’s accounts receivable and contract liabilities during the three months ended March 31, 2021 and 2020 (in thousands):
Balance at Beginning of Period
Additions
Deductions
Balance at End of Period
Three Months Ended March 31, 2021
Accounts receivable
$
2,130
$
953
$
(2,130
)
$
953
Contract liabilities:
Deferred revenue
$
73,931
$
-
$
(5,558
)
$
68,373
Balance at Beginning of Period
Additions
Deductions
Balance at End of Period
Three Months Ended March 31, 2020
Accounts receivable
$
4,620
$
9,765
$
(1,017
)
$
13,368
Contract liabilities:
Deferred revenue
$
28,810
$
-
$
(3,151
)
$
25,659
Summary of Revenues Recognized Resulting From Changes in Contract Liability BalanceDuring the three months ended March 31, 2021 and 2020, the Company recognized the following revenues as a result of changes in the contract liability balance (in thousands):
Three Months Ended March 31,
Revenue recognized in the period from:
2021
2020
Amounts included in the contract liability at the beginning of the period
$
5,558
$
3,151

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)3 Months Ended
Mar. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Equity-Based Compensation ExpenseEquity-based compensation expense is classified in the condensed consolidated statements of operations and comprehensive loss as follows:
Three Months Ended March 31,
2021
2020
(In thousands)
Research and development
$
3,491
$
2,160
General and administrative
2,933
1,997
Total
$
6,424
$
4,157
Summary of Restricted Stock ActivityThe following table summarizes the Company’s restricted stock activity for the three months ended March 31, 2021:
Number of Shares
Weighted Average Grant Date Fair Value per Share
Unvested restricted stock as of December 31, 2020
193,936
$
23.98
Granted
259,839
57.71
Vested
-
-
Cancelled
(11,035
)
27.59
Unvested restricted stock as of March 31, 2021
442,740
$
43.69
Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted Weighted average assumptions used to apply this pricing model were as follows:
Three Months Ended March 31,
2021
2020
Risk-free interest rate
0.9%
1.0%
Expected life of options
6.0 years
6.0 years
Expected volatility of underlying stock
72.0%
66.7%
Expected dividend yield
0.0%
0.0%
Summary of Stock Option ActivityThe following is a summary of stock option activity for the three months ended March 3 1 , 20 2 1 :
Number of Options
Weighted Average Exercise Price per Share
Weighted Average Remaining Contractual Term
Aggregate Intrinsic Value
(In years)
(In thousands)
Outstanding at December 31, 2020
6,977,440
$
15.43
Granted
1,645,823
57.94
Exercised
(1,014,569
)
13.15
Forfeited
(129,393
)
20.71
Outstanding at March 31, 2021
7,479,301
$
25.00
8.25
$
413,258
Exercisable at March 31, 2021
2,734,966

Loss Per Share (Tables)

Loss Per Share (Tables)3 Months Ended
Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per ShareBasic and diluted loss per share was calculated as follows:
Three Months Ended March 31,
2021
2020
(In thousands)
Net loss
$
(46,205
)
$
(31,806
)
Weighted average shares outstanding, basic and diluted
67,183
50,491
Net loss per share, basic and diluted
$
(0.69
)
$
(0.63
)
Potential Dilutive Securities Excluded from Computation of Diluted Net Loss Per Common ShareThe following common stock equivalents were excluded from the calculation of diluted loss per share because their inclusion would have been anti-dilutive:
Three Months Ended March 31,
2021
2020
(In thousands)
Unvested restricted stock
443
248
Stock options
7,479
7,243
7,922
7,491

Stockholders_ Equity (Tables)

Stockholders’ Equity (Tables)3 Months Ended
Mar. 31, 2021
Equity [Abstract]
Schedule of Changes in Stockholders’ EquityThe following tables present changes in stockholders’ equity for the three-month periods ended March 31, 2021 and 2020 (in thousands, except share data):
Additional
Accumulated Other
Total
Common
Paid-In
Comprehensive
Accumulated
Stockholders’
Shares
Amount
Capital
Income (Loss)
Deficit
Equity
Balance at December 31, 2020
66,234,056
$
7
$
962,173
$
1
$
(435,109
)
$
527,072
Issuance of common stock through at-the-market offerings, net of issuance costs of $52
641,709
-
45,255
-
-
45,255
Exercise of stock options
1,014,569
-
13,340
-
-
13,340
Equity-based compensation
-
-
6,424
-
-
6,424
Other comprehensive loss
-
-
-
(13
)
-
(13
)
Net loss
-
-
-
-
(46,205
)
(46,205
)
Balance at March 31, 2021
67,890,334
$
7
$
1,027,192
$
(12
)
$
(481,314
)
$
545,873
Additional
Accumulated Other
Total
Common
Paid-In
Comprehensive
Accumulated
Stockholders’
Shares
Amount
Capital
Income
Deficit
Equity
Balance at December 31, 2019
50,198,044
$
5
$
570,493
$
261
$
(300,878
)
$
269,881
Issuance of common stock through at-the-market offerings, net of issuance costs of $48
351,252
-
5,079
-
-
5,079
Exercise of stock options
53,579
-
336
-
-
336
Equity-based compensation
-
-
4,157
-
-
4,157
Other comprehensive income
-
-
-
112
-
112
Net loss
-
-
-
-
(31,806
)
(31,806
)
Balance at March 31, 2020
50,602,875
$
5
$
580,065
$
373
$
(332,684
)
$
247,759

Overview and Basis of Present_2

Overview and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands3 Months Ended71 Months Ended
Mar. 31, 2021Mar. 31, 2020Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering $ 1,165,300
Proceeds from issuance of convertible preferred stock85,000
Collaborative Arrangement [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering275,000
Initial Public Offering and Concurrent Private Placements [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering170,500
Follow-on public Offerings [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering438,300
At The Market Offerings [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering $ 45,255 $ 4,528 $ 196,500

Marketable Securities - Summary

Marketable Securities - Summary of Available -for-sale Marketable Securities (Detail) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Marketable Securities [Line Items]
Amortized Cost $ 459,272 $ 437,350
Gross Unrealized Gains58 23
Gross Unrealized Losses(70)(22)
Estimated Fair Value459,260 437,351
U.S. Treasury and Other Government Securities [Member]
Marketable Securities [Line Items]
Amortized Cost204,473 245,666
Gross Unrealized Gains49 13
Gross Unrealized Losses(4)(11)
Estimated Fair Value204,518 245,668
Financial Institution Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost169,979 138,445
Gross Unrealized Gains7 6
Gross Unrealized Losses(45)(8)
Estimated Fair Value169,941 138,443
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost51,311 41,765
Gross Unrealized Gains1 3
Gross Unrealized Losses(13)(2)
Estimated Fair Value51,299 41,766
Other Asset Backed Securities [Member]
Marketable Securities [Line Items]
Amortized Cost33,509 11,474
Gross Unrealized Gains1 1
Gross Unrealized Losses(8)(1)
Estimated Fair Value $ 33,502 $ 11,474

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($)3 Months Ended12 Months Ended
Mar. 31, 2021Dec. 31, 2020
Marketable Securities [Line Items]
Realized gains or losses on marketable securities $ 0 $ 0
Investments that matured beyond five years $ 0 $ 0
Minimum [Member]
Marketable Securities [Line Items]
Available-for-sales Securities, non-current, maturity period1 year
Maximum [Member]
Marketable Securities [Line Items]
Available-for-sales Securities, non-current, maturity period5 years

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Recognized at Fair Value on Recurring Basis (Detail) - Fair Value on Recurring Basis [Member] - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and restricted cash equivalents $ 143,129 $ 163,805
Marketable securities:
Marketable securities459,260 437,351
Total602,389 601,156
U.S. Treasury and Other Government Securities [Member]
Marketable securities:
Marketable securities204,518 245,668
Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities169,941 138,443
Corporate Debt Securities [Member]
Marketable securities:
Marketable securities51,299 41,766
Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities33,502 11,474
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and restricted cash equivalents143,129 163,805
Marketable securities:
Marketable securities181,118 241,664
Total324,247 405,469
Level 1 [Member] | U.S. Treasury and Other Government Securities [Member]
Marketable securities:
Marketable securities181,118 241,664
Level 2 [Member]
Marketable securities:
Marketable securities278,142 195,687
Total278,142 195,687
Level 2 [Member] | U.S. Treasury and Other Government Securities [Member]
Marketable securities:
Marketable securities23,400 4,004
Level 2 [Member] | Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities169,941 138,443
Level 2 [Member] | Corporate Debt Securities [Member]
Marketable securities:
Marketable securities51,299 41,766
Level 2 [Member] | Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities $ 33,502 $ 11,474

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in ThousandsMar. 31, 2021Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued research and development $ 10,010 $ 11,008
Employee compensation and benefits6,244 10,920
Accrued legal and professional expenses2,833 1,876
Accrued other2,128 1,750
Total accrued expenses $ 21,215 $ 25,554

Collaborations - Additional Inf

Collaborations - Additional Information (Detail) - USD ($)3 Months Ended60 Months Ended
Mar. 31, 2021Mar. 31, 2020Mar. 31, 2021Dec. 31, 2020Dec. 31, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue $ 6,445,000 $ 12,916,000
Deferred revenue68,373,000 25,659,000 $ 68,373,000 $ 73,931,000 $ 28,810,000
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions145,000,000
Collaboration revenue $ 6,400,000 7,900,000 129,700,000
Aggregate transaction price remaining to be recognized, periodThrough March 31, 2021
Payments due $ 900,000 $ 4,800,000
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Agreement [Member] | Research and Development Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue35,600,000
Regeneron Pharmaceuticals Inc. [Member] | Regeneron Amendment [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate transaction price remaining to be recognized68,400,000 68,400,000
Accounts receivable1,000,000 1,000,000 2,100,000
Deferred revenue $ 68,400,000 68,400,000 73,900,000
Novartis [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Strategic collaboration agreement amended date2018-12
Novartis [Member] | Regeneron Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue $ 5,000,000
Deferred revenue0 0 0
Accounts receivable $ 0 $ 0 $ 0

Collaborations - Summary of Cha

Collaborations - Summary of Changes in Accounts Receivable and Contract Liabilities (Detail) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Accounts receivable:
Accounts receivable, Balance at Beginning of Period $ 2,130 $ 4,620
Accounts receivable, Additions953 9,765
Accounts receivable, Deductions(2,130)(1,017)
Accounts receivable, Balance at End of Period953 13,368
Contract liabilities:
Deferred revenue, Balance at Beginning of Period73,931 28,810
Deferred revenue, Deductions(5,558)(3,151)
Deferred revenue, Balance at End of Period $ 68,373 $ 25,659

Collaborations - Summary of Rev

Collaborations - Summary of Revenues Recognized Resulting From Changes in Contract Liability Balance (Detail) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Revenue From Contract With Customer [Abstract]
Amounts included in the contract liability at the beginning of the period $ 5,558 $ 3,151

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands3 Months Ended
Mar. 31, 2021USD ($)ft²USD_per_sqftDec. 31, 2020USD ($)
Lessee Lease Description [Line Items]
Operating lease right-of-use assets $ 77,912 $ 39,114
Albany Lease [Member]
Lessee Lease Description [Line Items]
Area of space leased | ft²39,000
Operating lease, descriptionIn March 2020, the Company entered into an agreement to lease approximately 39,000 square feet of office and laboratory space at 281 Albany Street in Cambridge, Massachusetts under an operating lease agreement (the “281 Albany Lease”). The Company’s obligation to pay rent will start on the date that is six months after the commencement date or the date on which the Company occupies the premises, whichever occurs earlier (the “Rent Commencement Date”).
Term of lease10 years
Base rent per square foot for first year | USD_per_sqft99
Base rent per square foot for last year | USD_per_sqft128.87
Operating lease right-of-use assets $ 40,400
Operating lease, liability $ 34,800
Incremental borrowing rate5.52%
Prepaid lease payments $ 5,600
Amount receivable on cost of construction and tenant improvement $ 4,400
Operating lease, existence of option to extendtrue
Operating lease, options to extendThe Company has the option to extend the 281 Albany Lease for two successive five-year terms.
Albany Lease [Member] | Other Assets [Member]
Lessee Lease Description [Line Items]
Letter of credit $ 1,900

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions1 Months Ended3 Months Ended
Mar. 31, 2021Mar. 31, 2021Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period4 years
Weighted Average Grant Date Fair Value per Share, Granted $ 57.71
Number of Shares, Granted259,839
Unrecognized equity-based compensation expense related to restricted stock $ 17.8 $ 17.8
Weighted average grant date fair value per share $ 36.64 $ 7.96
Total intrinsic value of stock options exercised $ 54.8 $ 0.3
Unrecognized compensation cost related to stock options $ 86.9 $ 86.9
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Date Fair Value per Share, Granted $ 57.71
Number of Shares, Granted259,839
Weighted average period of unrecognized compensation costs3 years 7 months 6 days
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period3 years
Weighted Average Grant Date Fair Value per Share, Granted $ 15.05
Number of Shares, Granted107,360
Additional vesting of shares0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period of unrecognized compensation costs3 years 2 months 12 days
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining vesting period3 years
Description of stock options granted under the PlanStock options granted under the 2015 Plan generally vest 25% on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years, unless they contain specific performance-based vesting provisions. The maximum term of stock options granted under the 2015 Plan is ten years.
Shares available for future issuance2,890,540 2,890,540
Percentage of cumulative increase in number of shares for future issuance4.00%
2015 Plan [Member] | First Anniversary of Original Vesting Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vest percentage on the first anniversary25.00%
Maximum [Member] | 2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of stock options granted10 years

Equity-Based Compensation - Sch

Equity-Based Compensation - Schedule of Equity-Based Compensation Expense (Detail) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense $ 6,424 $ 4,157
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense3,491 2,160
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense $ 2,933 $ 1,997

Equity-Based Compensation - Sum

Equity-Based Compensation - Summary of Restricted Stock Activity (Detail)3 Months Ended
Mar. 31, 2021$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Unvested, Beginning balance | shares193,936
Number of Shares, Granted | shares259,839
Number of Shares, Cancelled | shares(11,035)
Number of Shares, Unvested, Ending balance | shares442,740
Weighted Average Grant Date Fair Value per Share, Unvested, Beginning balance | $ / shares $ 23.98
Weighted Average Grant Date Fair Value per Share, Granted | $ / shares57.71
Weighted Average Grant Date Fair Value per Share, Cancelled | $ / shares27.59
Weighted Average Grant Date Fair Value per Share, Unvested, Ending balance | $ / shares $ 43.69

Equity-Based Compensation - S_2

Equity-Based Compensation - Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted (Detail)3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate0.90%1.00%
Expected life of options6 years6 years
Expected volatility of underlying stock72.00%66.70%
Expected dividend yield0.00%0.00%

Equity-Based Compensation - S_3

Equity-Based Compensation - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands3 Months Ended
Mar. 31, 2021USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Outstanding, Beginning Balance6,977,440
Number of options, Granted1,645,823
Number of options, Exercised(1,014,569)
Number of options, Forfeited(129,393)
Number of Options, Outstanding, Ending Balance7,479,301
Number of Options, Exercisable2,734,966
Weighted Average Exercise Price per Share, Outstanding, Beginning Balance | $ / shares $ 15.43
Weighted Average Exercise Price per Share, Granted | $ / shares57.94
Weighted Average Exercise Price per Share, Exercised | $ / shares13.15
Weighted Average Exercise Price per Share, Forfeited | $ / shares20.71
Weighted Average Exercise Price per Share, Outstanding, Ending Balance | $ / shares $ 25
Weighted Average Remaining Contractual Term, Outstanding8 years 3 months
Aggregate Intrinsic Value, Outstanding | $ $ 413,258

Loss Per Share - Schedule of Ba

Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Earnings Per Share [Abstract]
Net loss $ (46,205) $ (31,806)
Weighted average shares outstanding, basic and diluted67,183 50,491
Net loss per share, basic and diluted $ (0.69) $ (0.63)

Loss Per Share - Potential Dilu

Loss Per Share - Potential Dilutive Securities Excluded from Computation of Diluted Net Loss Per Common Share (Detail) - shares shares in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share7,922 7,491
Unvested Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share443 248
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share7,479 7,243

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Changes in Stockholders Equity (Detail) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
Class Of Stock [Line Items]
Beginning balance $ 527,072 $ 269,881
Beginning balance, shares66,234,056
Exercise of stock options $ 13,340 336
Exercise of stock options, shares1,014,569
Equity-based compensation $ 6,424 4,157
Other comprehensive income (loss)(13)112
Net loss(46,205)(31,806)
Ending balance $ 545,873 247,759
Ending balance, shares67,890,334
At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock $ 45,255 5,079
Common Stock [Member]
Class Of Stock [Line Items]
Beginning balance $ 7 $ 5
Beginning balance, shares66,234,056 50,198,044
Exercise of stock options, shares1,014,569 53,579
Ending balance $ 7 $ 5
Ending balance, shares67,890,334 50,602,875
Common Stock [Member] | At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock, shares641,709 351,252
Additional Paid-In Capital [Member]
Class Of Stock [Line Items]
Beginning balance $ 962,173 $ 570,493
Exercise of stock options13,340 336
Equity-based compensation6,424 4,157
Ending balance1,027,192 580,065
Additional Paid-In Capital [Member] | At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock45,255 5,079
Accumulated Other Comprehensive Income (Loss) [Member]
Class Of Stock [Line Items]
Beginning balance1 261
Other comprehensive income (loss)(13)112
Ending balance(12)373
Accumulated Deficit [Member]
Class Of Stock [Line Items]
Beginning balance(435,109)(300,878)
Net loss(46,205)(31,806)
Ending balance $ (481,314) $ (332,684)

Stockholders' Equity - Schedu_2

Stockholders' Equity - Schedule of Changes in Stockholders Equity (Parenthetical) (Detail) - USD ($) $ in Thousands3 Months Ended
Mar. 31, 2021Mar. 31, 2020
At The Market Offerings [Member]
Class Of Stock [Line Items]
Stock issuance cost,net $ 52 $ 48

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions1 Months Ended3 Months Ended12 Months Ended71 Months Ended
Aug. 31, 2019Mar. 31, 2021Mar. 31, 2020Dec. 31, 2019Mar. 31, 2021
Class Of Stock [Line Items]
Proceeds from common stock offering $ 1,165.3
2019 Sales Agreement [Member]
Class Of Stock [Line Items]
Proceeds from common stock offering $ 5.1 $ 45.3
Percentage of gross proceeds from common stock as sales agent cash commission3.00%
Number of common stock issued upon conversion of shares641,709 351,252
Common stock price per share $ 15.05 $ 72.79 $ 15.05
Proceeds from common stock offering $ 47.4 $ 47.4
2019 Sales Agreement [Member] | General and Administrative Expenses [Member]
Class Of Stock [Line Items]
Legal accounting and other fees $ 0.1 $ 0.1
2019 Sales Agreement [Member] | Maximum [Member]
Class Of Stock [Line Items]
Proceeds from common stock offering $ 150