Relay Therapeutics (RLAY) 10-Q 10 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 08, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	Relay Therapeutics, Inc.
Entity Central Index Key	0001812364
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Address, State or Province	MA
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	RLAY
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		108,044,143
Entity File Number	001-39385
Entity Tax Identification Number	47-3923475
Entity Address Address Line1	399 Binney Street
Entity Address, Address Line Two	2nd Floor
Entity Address, City or Town	Cambridge
Entity Address, Postal Zip Code	02139
City Area Code	617
Local Phone Number	370-8837

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 228,559	$ 447,646
Investments	387,949	230,415
Accounts receivable	804	75,000
Contract asset	4,251	7,654
Prepaid expenses and other current assets	17,696	9,385
Total current assets	639,259	770,100
Property and equipment, net	6,239	6,250
Operating lease assets	21,239	22,579
Restricted cash	2,578	878
Intangible asset	2,300
Other assets		22
Total assets	671,615	799,829
Current liabilities:
Accounts payable	6,316	6,351
Accrued expenses and other current liabilities	20,102	5,760
Operating lease liabilities	1,768	1,521
Deferred revenue	331
Total current liabilities	28,517	13,632
Operating lease liabilities, net of current portion	21,545	22,901
Restricted stock liability		3
Contingent consideration liability	50,465
Total liabilities	100,527	36,536
Commitments and contingencies (Note 10)
Stockholders’ equity:
Common stock, $0.001 par value; 150,000,000 shares authorized at September 30, 2021 and December 31, 2020; 92,800,072 and 89,991,324 shares issued at September 30, 2021 and December 31, 2020, respectively; 92,800,072 and 89,906,835 shares outstanding at September 30, 2021 and December 31, 2020, respectively	92	90
Additional paid-in capital	1,271,630	1,167,367
Accumulated other comprehensive income	10	64
Accumulated deficit	(700,644)	(404,228)
Total stockholders’ equity	571,088	763,293
Total liabilities and stockholders’ equity	$ 671,615	$ 799,829

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Common stock par value	$ 0.001	$ 0.001
Common stock shares authorized	150,000,000	150,000,000
Common stock shares issued	92,800,072	89,991,324
Common stock shares outstanding	92,800,072	89,906,835
Undesignated Preferred Stock [Member]
Preferred stock par value	$ 0.001	$ 0.001
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue:
Collaboration revenue	$ 666		$ 2,462
Revenue from Contract with Customer, Product and Service [Extensible List]	rlay:CollaborationRevenueMember	rlay:CollaborationRevenueMember	rlay:CollaborationRevenueMember	rlay:CollaborationRevenueMember
Total revenue	$ 666		$ 2,462
Operating expenses:
Research and development expenses	44,974	$ 24,376	120,743	$ 67,739
In-process research and development expenses			123,000
Loss on initial consolidation of variable interest entity			11,855
Change in fair value of contingent consideration liability	2,000		2,000
General and administrative expenses	14,682	12,231	41,839	23,045
Total operating expenses	61,656	36,607	299,437	90,784
Loss from operations	(60,990)	(36,607)	(296,975)	(90,784)
Other income (expense):
Interest income	157	534	563	3,104
Other income (expense)		(5)	(4)	(8)
Total other income (expense), net	157	529	559	3,096
Net loss	(60,833)	(36,078)	(296,416)	(87,688)
Deemed dividend resulting from extinguishment upon modification of Series C preferred stock		(177,789)		(177,789)
Net loss attributable to common stockholders	$ (60,833)	$ (213,867)	$ (296,416)	$ (265,477)
Net loss per share, basic and diluted	$ (0.66)	$ (3)	$ (3.20)	$ (9.92)
Weighted average shares of common stock, basic and diluted	92,692,515	71,248,846	92,599,781	26,766,687
Other comprehensive (loss) income:
Unrealized holding (loss) gain	$ 74	$ (455)	$ (54)	$ (149)
Total other comprehensive (loss) income	74	(455)	(54)	(149)
Total comprehensive loss	$ (60,759)	$ (36,533)	$ (296,470)	$ (87,837)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2019	$ (180,438)	$ 537,781	$ 4	$ 8,715	$ 325	$ (189,482)
Beginning balance, shares at Dec. 31, 2019		212,642,857	4,037,476
Issuance of common stock upon exercise of stock options	351			351
Issuance of common stock upon exercise of stock options, shares			85,845
Vesting of restricted common stock	98			98
Vesting of restricted common stock, shares			210,516
Stock-based compensation expense	1,455			1,455
Unrealized gain (loss) on investments	1,069				1,069
Net loss	(24,886)					(24,886)
Ending balance at Mar. 31, 2020	(202,351)	$ 537,781	$ 4	10,619	1,394	(214,368)
Ending balance, shares at Mar. 31, 2020		212,642,857	4,333,837
Beginning balance at Dec. 31, 2019	(180,438)	$ 537,781	$ 4	8,715	325	(189,482)
Beginning balance, shares at Dec. 31, 2019		212,642,857	4,037,476
Net loss	(87,688)
Ending balance at Sep. 30, 2020	713,525	$ 0	$ 90	1,152,763	176	(439,504)
Ending balance, shares at Sep. 30, 2020			89,803,785
Beginning balance at Mar. 31, 2020	(202,351)	$ 537,781	$ 4	10,619	1,394	(214,368)
Beginning balance, shares at Mar. 31, 2020		212,642,857	4,333,837
Issuance of common stock upon exercise of stock options	367			367
Issuance of common stock upon exercise of stock options, shares			95,573
Vesting of restricted common stock	47		$ 1	46
Vesting of restricted common stock, shares			163,321
Stock-based compensation expense	4,032			4,032
Unrealized gain (loss) on investments	(763)				(763)
Net loss	(26,724)					(26,724)
Ending balance at Jun. 30, 2020	(225,392)	$ 537,781	$ 5	15,064	631	(241,092)
Ending balance, shares at Jun. 30, 2020		212,642,857	4,592,731
Extinguishment upon modification of Series C preferred stock	(177,789)	$ 177,789		(15,455)		(162,334)
Conversion of convertible preferred stock into common stock upon initial public offering	715,570	$ (715,570)	$ 62	715,508
Conversion of convertible preferred stock into common stock upon initial public offering, shares		(212,642,857)	61,992,534
Issuance of common stock in public offering, net of discounts and issuance costs of $34,707	425,293		$ 23	425,270
Issuance of common stock in public offering, net of discounts and issuance costs of $34,707, shares			23,000,000
Issuance of common stock upon exercise of stock options	442			442
Issuance of common stock upon exercise of stock options, shares			101,861
Vesting of restricted common stock	5			5
Vesting of restricted common stock, shares			116,659
Stock-based compensation expense	11,929			11,929
Unrealized gain (loss) on investments	(455)				(455)
Net loss	(36,078)					(36,078)
Ending balance at Sep. 30, 2020	713,525	$ 0	$ 90	1,152,763	176	(439,504)
Ending balance, shares at Sep. 30, 2020			89,803,785
Beginning balance at Dec. 31, 2020	763,293		$ 90	1,167,367	64	(404,228)
Beginning balance, shares at Dec. 31, 2020			89,906,835
Issuance of common stock upon exercise of stock options	2,055			2,055
Issuance of common stock upon exercise of stock options, shares			437,230
Vesting of restricted common stock	3			3
Vesting of restricted common stock, shares			84,489
Stock-based compensation expense	9,671			9,671
Unrealized gain (loss) on investments	(52)				(52)
Net loss	(42,184)					(42,184)
Ending balance at Mar. 31, 2021	732,786		$ 90	1,179,096	12	(446,412)
Ending balance, shares at Mar. 31, 2021			90,428,554
Beginning balance at Dec. 31, 2020	763,293		$ 90	1,167,367	64	(404,228)
Beginning balance, shares at Dec. 31, 2020			89,906,835
Net loss	(296,416)
Ending balance at Sep. 30, 2021	571,088		$ 92	1,271,630	10	(700,644)
Ending balance, shares at Sep. 30, 2021			92,800,072
Beginning balance at Mar. 31, 2021	732,786		$ 90	1,179,096	12	(446,412)
Beginning balance, shares at Mar. 31, 2021			90,428,554
Issuance of common stock upon exercise of stock options	1,123			1,123
Issuance of common stock upon exercise of stock options, shares			218,365
Vesting of restricted common stock, shares			22,239
Stock-based compensation expense	16,147			16,147
Shares issued in connection with acquisition of ZebiAI	61,948		$ 2	61,946
Shares issued in connection with acquisition, shares			1,883,487
Unrealized gain (loss) on investments	(76)				(76)
Net loss	(193,399)					(193,399)
Ending balance at Jun. 30, 2021	618,529		$ 92	1,258,312	(64)	(639,811)
Ending balance, shares at Jun. 30, 2021			92,552,645
Issuance of common stock upon exercise of stock options	900			900
Issuance of common stock upon exercise of stock options, shares			196,076
Vesting of restricted common stock, shares			51,351
Stock-based compensation expense	12,418			12,418
Unrealized gain (loss) on investments	74				74
Net loss	(60,833)					(60,833)
Ending balance at Sep. 30, 2021	$ 571,088		$ 92	$ 1,271,630	$ 10	$ (700,644)
Ending balance, shares at Sep. 30, 2021			92,800,072

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical) $ in Thousands	3 Months Ended
	Sep. 30, 2020USD ($)
Statement Of Stockholders Equity [Abstract]
Net of discounts and issuance costs	$ 34,707

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (296,416)	$ (87,688)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	38,236	17,416
Depreciation expense	2,891	2,637
Net amortization of premiums and discounts on investments	1,371	(430)
Acquired in-process research and development	123,000
Loss on initial consolidation of variable interest entity	11,855
Change in fair value of contingent consideration liability	2,000
Changes in assets and liabilities:
Prepaid expenses and other current assets	(7,147)	(3,664)
Lease assets and liabilities, net	231	271
Accounts payable	(1,503)	(1,693)
Accrued expenses and other liabilities	13,082	5,934
Accounts receivable	74,276
Contract asset	3,403
Other assets	22
Net cash used in operating activities	(34,699)	(67,217)
Cash flows from investing activities:
Purchases of property and equipment	(2,591)	(1,867)
Purchases of investments	(653,633)	(140,097)
Proceeds from maturities of investments	494,673	300,056
Cash paid for acquisition of ZebiAI, net of cash acquired	(25,215)
Net cash (used in) provided by investing activities	(186,766)	158,092
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	4,078	1,160
Proceeds from issuance of common stock upon initial public offering		427,800
Offering costs paid		(2,507)
Net cash provided by financing activities	4,078	426,453
Net (decrease) increase in cash, cash equivalents and restricted cash	(217,387)	517,328
Cash, cash equivalents and restricted cash at beginning of period	448,524	42,832
Cash, cash equivalents and restricted cash at end of period	231,137	560,160
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment additions included in accounts payable and accrued expenses	33
Reclassification of restricted stock liability to additional paid-in capital	3	150
Assets obtained in asset acquisition	662
Liabilities assumed in asset acquisition	2,330
Extinguishment upon modification of series C preferred stock		(177,789)
Conversion of preferred stock into common stock upon initial public offering		$ 715,508
Fair value of equity issued in connection with asset acquisition	$ 61,948

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Restricted Cash And Cash Equivalents At Carrying Value [Abstract]
Cash and cash equivalents	$ 228,559	$ 447,646	$ 559,282
Restricted cash	2,578	878	878
Total cash, cash equivalents and restricted cash as shown on condensed consolidated statements of cash flows	$ 231,137	$ 448,524	$ 560,160	$ 42,832

Nature of Business and Basis of

Nature of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Text Block [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation Relay Therapeutics, Inc. (the “Company”) was incorporated in Delaware on May 4, 2015 and is headquartered in Cambridge, Massachusetts. The Company is a clinical-stage, precision medicines company transforming the drug discovery process by combining leading-edge computational and experimental technologies with the goal of bringing life-changing therapies to patients. The Company is among the first of a new breed of biotech created at the intersection of disparate disciplines. The Company’s Dynamo™ platform integrates an array of leading-edge computational and experimental approaches designed to drug protein targets that have previously been intractable or inadequately addressed. The Company’s initial focus is on enhancing small molecule therapeutic discovery in targeted oncology and genetic disease indications. The Company is advancing its pipeline of medicines to address targets in precision oncology, including its lead product candidates, RLY-4008, RLY-2608 and RLY-1971. The Company initiated a Phase 1 clinical trial for RLY-1971 in patients with advanced solid tumors in the first quarter of 2020 and a first-in-human clinical trial of RLY-4008 enriched for patients with advanced solid tumors having oncogenic FGFR2 alterations in the third quarter of 2020. In December 2020, the Company entered into the Collaboration and License Agreement (the “Genentech Agreement”) with Genentech, Inc. (“Genentech”), a member of the Roche Group, for the development and commercialization of RLY-1971, as further discussed in Note 6. The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive pre-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. The Company’s product candidates are in development. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees and consultants. The Company has devoted substantially all of its resources to developing its product candidates, including RLY-4008, RLY-2608 and RLY-1971 by developing its innovative computational and experimental approaches, building its intellectual property portfolio, business planning, raising capital and providing general and administrative support for these operations. The Company has incurred net operating losses since inception and had an accumulated deficit of $700.6

Significant Accounting Policie

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) for interim information and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for reporting on Form 10-Q. The Company’s condensed consolidated financial statements include the accounts of Relay Therapeutics, Inc. and its wholly-owned subsidiaries, Relay Therapeutics Securities Corporation and Relay ML Discovery, LLC. All intercompany balances and transactions have been eliminated. Unaudited Interim Financial Information The accompanying condensed consolidated balance sheet as of September 30, 2021 , the condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2021 and 2020, the condensed consolidated statements of stockholders’ equity (deficit) for the three and nine months ended September 30, 2021 and 2020, and the condensed consolidated statements of cash flows for the nine months ended September 30, 2021 and 20 20 are unaudited. The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s condensed consolidated financial position as of September 30, 2021 , the condensed consolidated results of its operations for the three and nine months ended September 30, 2021 and 2020 and cash flows for the nine months ended September 30, 2021 and 20 2 0 . The condensed consolidated financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2021 and 20 20 are unaudited. The condensed consolidated results for the three and nine months ended September 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 202 1 , any other interim periods, or any future year or period. 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 condensed consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual of research and development and manufacturing expenses, the valuation of equity instruments, the determination of the transaction price and standalone selling price of performance obligations under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, including expenses, clinical trials and research and development costs, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19, as well as the economic impact on local, regional, national and international markets. The Company has made estimates of the impact of COVID-19 within its financial statements and there may be changes to those estimates in future periods. Actual results could differ from the Company’s estimates. Collaboration Agreements The Company enters into collaborative agreements with third parties to research, develop and commercialize drug candidates, pursuant to which the risks and rewards for such activities are shared between the parties. Such arrangements also provide for cost sharing between the parties during the research and development phase, as well as potential future profit share payments during the commercialization phase. In general, such contracts are evaluated under the provisions of FASB ASC 808, Collaborative Arrangements Acquired In-Process Research and Development In an asset acquisition, the cost allocated to acquire in-process research and development (“IPR&D”) with no alternative future use is charged to expense at the acquisition date. Refer to Note 5, Acquisition of ZebiAI, for a more detailed description of the accounting policies applied to the recent asset acquisition. Recently Adopted Accounting Pronouncements Effective January 1, 2021, the Company adopted FASB Accounting Standards Update (“ASU”) No. 2020-06, Debt – Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity’s Own Equity Effective January 1, 2021, the Company adopted ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments the Company is based on an incurred losses model. For available-for-sale debt securities with expected credit losses, this standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. The Company will become a large accelerated filer for the fiscal year ending December 31, 2022 and, therefore, be required to adopt th is standard on January 1, 2022. The Company is assessing the impact of ASU 20 16 - 13 on the condensed consolidated financial statements and disclosures and does not expect it to have a material impact on the Company’s condensed consolidated financial statements or disclosures . From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that the Company adopts as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected to use the extended transition period related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different effective dates for public and nonpublic companies, the Company can adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and can do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. As noted above, the Company will become a large accelerated filer for the fiscal year ending December 31, 2021, and as such it will lose emerging growth status as of that date.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of September 30, 2021: Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 216,195 $ — $ — $ 216,195 Investments: US treasury bills — 256,668 — 256,668 US agency securities — 131,281 — 131,281 Total investments — 387,949 — 387,949 Total assets $ 216,195 $ 387,949 $ — $ 604,144 Liabilities Contingent consideration — — 45,465 45,465 Total liabilities $ — $ — $ 45,465 $ 45,465 Fair Value Measurements as of December 31, 2020: Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 447,146 $ — $ — $ 447,146 Investments: US treasury bills — 33,026 — 33,026 US agency securities — 197,389 — 197,389 Total investments — 230,415 — 230,415 Total $ 447,146 $ 230,415 $ — $ 677,561 In determining the fair value of its investments at each date presented above, the Company relied on quoted prices for similar securities in active markets or using other inputs that are observable or can be corroborated by observable market data. Fair Value of Contingent Consideration In April 2021, the Company acquired ZebiAI Therapeutics, Inc. (“ZebiAI”). The Company’s Level 3 contingent consideration liability is related to $85.0 million of platform and program-related milestones (“Contingent Milestone Payments”) potentially payable to ZebiAI’s former equity holders, measured at $43.5 million as of the acquisition date and $45.5 million as of September 30, 2021. The Company determines the fair value of the contingent payments based on the probability of achieving the milestones, the related timing and an appropriate discount rate. Significant judgment is used in determining the appropriateness of these assumptions. The contingent consideration liability for the Contingent Milestone Payments is measured at fair value at each reporting date pursuant to FASB ASC Topic 480, Distinguishing Liabilities from Equity resulting in adjustments to the fair value of the Company’s Contingent Milestone Payments, and the effect of any such adjustments could be material. The contingent consideration associated with the $ 100.0 million earnout payments (“Contingent Earnout Payments”) is a nonrecurring fair value measure, as further discussed in Note 5. The following table reconciles the change in fair value of the contingent consideration liability based on level 3 inputs (in thousands): Nine Months Ended September 30, 2021 Balance at December 31, 2020 $ — Contingent consideration related to acquisition of ZebiAI 43,465 Increase in fair value of contingent payments 2,000 Balance at September 30, 2021 $ 45,465 The “Increase in fair value of contingent payments” in the table above was primarily attributable to the time value of money.

Investments

Investments	9 Months Ended
	Sep. 30, 2021
Schedule Of Investments [Abstract]
Investments	4. Investments The fair value of available-for-sale investments by type of security was as follows: September 30, 2021 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Investments: U.S treasury bills $ 117,993 $ 13 $ — $ 118,006 U.S agency securities 29,497 1 — 29,498 Total investments with a maturity of one year or less 147,490 14 — 147,504 U.S treasury bills 138,675 — (13 ) 138,662 U.S agency securities 101,774 9 — 101,783 Total investments with a maturity of one to two years 240,449 9 (13 ) 240,445 Total investments $ 387,939 $ 23 $ (13 ) $ 387,949 December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Investments: U.S treasury bills $ 29,997 $ 21 $ — $ 30,018 U.S agency securities 20,996 5 — 21,001 Total investments with a maturity of one year or less 50,993 26 — 51,019 U.S treasury bills 3,008 — — 3,008 U.S agency securities 176,350 38 — 176,388 Total investments with a maturity of one to two years 179,358 38 — 179,396 Total investments $ 230,351 $ 64 $ — $ 230,415

Acquisition of ZebiAI

Acquisition of ZebiAI	9 Months Ended
	Sep. 30, 2021
Business Combination Description [Abstract]
Acquisition of ZebiAI	5. Acquisition of ZebiAI On April 22, 2021 (the “Acquisition Date”), the Company acquired ZebiAI, a privately held company focused on using machine learning combined with DNA encoded library data sets for drug discovery. Pursuant to the Agreement and Plan of Merger (the “Merger Agreement”), the Company was required to pay ZebiAI’s former stockholders, option holders and warrant holders (“the ZebiAI Holders”) upfront consideration of approximately $20.0 million in cash and issued 1,883,487 shares of the Company’s common stock at an aggregate fair value of $60.8 million. In addition, (i) the ZebiAI Holders will be eligible to receive up to an additional $85.0 million in milestone payments upon the achievement of certain platform or program-related milestones, payable in common stock (the “Contingent Milestone Payments”), and (ii) the Company will pay to the ZebiAI Holders 10% of the payments it receives within three years of the closing date of the Merger Agreement from partnering, collaboration or other agreements related to ZebiAI’s platform up to an aggregate maximum amount of $100.0 million, payable in cash (the “Contingent Earnout Payments”). The Company first assessed if ZebiAI represented an asset or a business under FASB ASC Topic 805, Business Combinations (“ASC 805”), as amended by ASU 2017-01. Under ASC 805, the Company determined that ZebiAI did not constitute a business since substantially all of the fair value of the gross assets acquired is concentrated in a single asset, which is the intellectual property for the AI platform and the related data sets in development by ZebiAI. The intellectual property acquired from ZebiAI is at an early stage of development and will require a significant investment of time and capital for development. There is no assurance that the Company will be successful in completing the additional research and development activities. The Company also determined that the acquisition represented an initial consolidation of a variable interest entity that does not constitute a business in accordance with FASB Topic 810, Consolidation (“ASC 810”), primarily as a result of the fact that ZebiAI was deemed to be a variable interest entity as it did not have sufficient equity to finance its activities without additional subordinated financial support . Prior to the Acquisition Date, the source of funding for ZebiAl ha d primarily been preferred stock financings and convertible notes . The Company acquired all of the outstanding shares of ZebiAI, and therefore is the sole equity holder. The Company will absorb the losses of ZebiAi , has the rights to the benefits derived from the ZebiAi platform and the power to direct all activities, and therefore is the primary beneficiary. As a result, the net assets acquired and liabilities assumed in connection with the ZebiAI acquisition were recorded at their estimated fair values as of the Acquisition Date. Total consideration transferred of $ million included the cash and shares issued to ZebiAI Holders, the fair value of the Contingent Milestone Payments and the Contingent Earnout Payments and an insignificant amount attributed to the replacement of stock options to ZebiAI Holders. The Contingent Milestone P ayments were determined to be liabilities pursuant to ASC 480 and therefore were included in consideration transferred. The Contingent Earnout Payments were required to be included in total consideration transferred as a result of ASC 810. The difference between total consideration transferred and the fair value of net assets acquired and liabilities assumed of $ million was recorded as loss on initial consolidation of a variable interest entity pursuant to ASC 810. The following table summarizes the net assets acquired based on their estimated fair values as of the Acquisition Date (in thousands): Acquired IPR&D asset $ 123,000 Loss on initial consolidation of VIE 11,855 Assets obtained in asset acquisition 662 Liabilities assumed in asset acquisition (2,330 ) Intangible asset 2,300 Net acquired assets $ 135,487 In the estimation of fair value of the acquired assets and liabilities assumed, the Company used the carrying value of the net working capital balances as the most reliable indicator of fair value based on the associated short-term nature of the balances. The remaining fair value was attributable to the acquired IPR&D and an intangible asset. The fair value attributable to the IPR&D asset was determined using an Avoided Cost Method that includes all costs to develop the IPR&D asset, including appropriate mark-ups on the cost estimate and an expected return related to developing the IPR&D asset over a period of time. The fair value of the IPR&D asset was expensed in the Company’s consolidated statements of operations and comprehensive loss for the nine months ended September 30, 2021 as the acquired IPR&D had no alternative future use, as determined by the Company in accordance with U.S. GAAP, including ASC 730. The intangible asset represents the assembled workforce, for which the Company concluded there were no indicators of impairment through September 30, 2021. The Company recorded a contingent consideration liability at the Acquisition Date based upon the fair value of the Contingent Milestone Payments and the Contingent Earnout Payments of $48.5 million. The Company is required to re-assess the fair value of the Contingent Milestone Payments at each reporting period pursuant to ASC 480 (refer to Note 3). Derivatives and Hedging,

Collaboration and License Arran

Collaboration and License Arrangements	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Arrangements	6. Collaboration and License Arrangements Discovery Collaboration Agreement with EQRx, Inc. In August 2021, the Company and EQRx, Inc. (“EQRx”), a related party, entered into the Discovery Collaboration Agreement (“Collaboration Agreement”) to discover, develop, and commercialize novel medicines against validated oncology targets. Under the terms of the Collaboration Agreement, the Company is responsible for the discovery phase through to filing of the application for an Investigational New Drug (“IND”), while EQRx is responsible for clinical development, regulatory and commercialization of the product candidates under the collaboration. Subject to certain opt-out rights, the Company and EQRx share equally in the discovery, development and commercialization costs, as well as the net profits and losses from sales of any collaboration medicines, if approved. The Company retains the right to develop any collaboration medicines in combination with its wholly-owned pipeline . The Company accounts for the Collaboration Agreement pursuant to its accounting policy on collaboration arrangements, as disclosed in Note 2. During the three months ended September 30, 2021, expenses related to the Collaboration Agreement were immaterial. Collaboration and License Agreement with Genentech, Inc. On December 11, 2020, the Company entered into the Genentech Agreement, which granted Genentech a license to develop and commercialize RLY-1971. RLY-1971 is currently being developed in a Phase 1a clinical trial for patients with advanced solid tumors (the “Phase 1a Trial”). Unless Genentech elects to exercise its option to conduct the remainder of the ongoing Phase 1a Trial, the Company is responsible for the completion of this trial. Genentech is responsible for conducting all subsequent clinical development of RLY-1971. The Company is also responsible for the one-time transfer of the active pharmaceutical ingredient (“API”) and other materials related to RLY-1971 to Genentech. Under the Genentech Agreement, the Company received a non-refundable upfront payment of $75.0 million, which was due upon completion of certain technology transfer activities and was reflected as accounts receivable on the consolidated balance sheet at December 31, 2020. The Company collected this amount in full in January 2021. In April 2021, the Company completed the transfer of the IND application for RLY-1971 to Genentech upon which the Company received payment for the associated non-refundable milestone payment of $5.0 million in May 2021. The Company is eligible to receive up to $20.0 million in additional near-term milestone payments. The Company is also eligible to receive up to an aggregate of an additional $695.0 million upon the achievement of specified development, commercialization and sales-based milestones for RLY-1971 worldwide as well as tiered royalties ranging from low-to-mid teens on annual worldwide net sales of RLY-1971, on a country-by-country basis, subject to reduction in certain circumstances. The Company has the option, exercisable one time at the Company’s sole discretion, to (a) fund half of the development costs of RLY-1971 in the United States, (b) share half of the net profits or net loss of commercializing RLY-1971 in the U.S. (the “Profit/Cost Share”) and (c) be eligible to receive up to an aggregate of an additional $410.0 million upon the achievement of specified commercialization and sales-based milestones for RLY-1971 outside of the United States and tiered royalties ranging from low-to-mid teens on annual net sales of RLY-1971 outside of the United States, on a country-by-country basis, subject to reduction in certain circumstances. The Company may elect to opt-out of further participation in the Profit/Cost Share at any time prior to the third anniversary of the first commercial sale of RLY-1971 in the U.S, in which case the financial terms would revert to the terms applicable as if the Company had not opted into the Profit/Cost Share as of the effective opt-out date. Genentech may terminate the Genentech Agreement for convenience and the Company may terminate the Genentech Agreement under certain limited circumstances. Unless otherwise terminated, the Genentech Agreement will remain in effect until the expiration of all Genentech’s royalty payment obligations to the Company. Accounting Analysis Identification of the Contract The Company concluded that Genentech is a customer in this arrangement and as such, the arrangement falls within the scope of the revenue recognition guidance in ASC 606. Identification of Performance Obligations At the commencement of the Genentech Agreement, the Company identified the following performance obligations in the agreement: • License to develop and commercialize RLY-1971 and the related know-how; • Research and development services to complete the Phase 1a Trial for RLY-1971; and • Transfer of API and other materials related to RLY-1971 The Company determined that the performance obligations outlined above are both capable of being distinct and distinct within the context of the contract given such rights and activities are independent of each other. The license can be used by Genentech without the research and development services or API outlined above, Determination of Transaction Price The Company determined the transaction price for the Genentech Agreement to be $86.3 million, which includes both fixed and variable consideration amounts. The total transaction price of $86.3 million is comprised of (i) the $75.0 million fixed, non-refundable upfront payment, (ii) a $5.0 million non-refundable milestone payment due upon the transfer of the IND application development services. No additional development milestone payments and no regulatory milestone payments are included in the transaction price as all such payments are fully constrained. As part of management’s evaluation of the constraint, the Company considered numerous factors, including the consideration that achievement of the milestones is outside of the Company’s control, contingent upon Genentech’s efforts and the receipt of regulatory approval and subject to scientific risks of success. Allocation of Transaction Price to Performance Obligations The Company allocated the transaction price of $86.3 million based on the stand-alone selling prices (“SSP”) of each of the performance obligations as follows: • $82.9 million for the transfer of the license • $3.0 million for research and development services; and • $0.4 million for the transfer of API. The SSP for the license was determined using an approach that considered discounted, probability-weighted cash flows related to the license transferred. The Company also reviewed comparable market transactions in determining the SSP of the license. The SSP for the research and development services as well as the transfer of API were based on estimates of the associated effort and cost of these services and cost to manufacture API, adjusted for a reasonable profit margin that would be expected to be realized under similar contracts. Recognition of Revenue The Company is recognizing revenue for each of the three performance obligations as follows: • The Company recognized revenue related to the license at a point in time upon transfer of the license to Genentech. The Company recognized the full amount allocated to the license and related know-how in the fourth quarter of 2020 because the Company had transferred the license upon execution of the Genentech Agreement. • The Company is satisfying the research and development performance obligation for RLY-1971 as the research and development services are performed. The research and development services performance obligation consists of the Company completing the Phase 1a clinical trial initiated in the first quarter of 2020. The Company recognizes revenue related to the research and development services over time using a cost-based input method by calculating actual costs incurred to date at each period end relative to total estimated costs expected to be incurred to fulfill the performance obligation. Revenue recognized during the three and nine months ended September 30, 2021 related to the R&D services amounts to $0.4 million and $1.4 million, respectively. • The Company recognized the full amount of revenue allocated to the transfer of API in the first quarter of 2021 upon transfer to Genentech in the amount of $0.4 million. There was no revenue recognized related to this performance obligation during the year ended December 31, 2020. During the three and nine months ended September 30, 2021 the Company recognized an aggregate of $0.4 million and $2.1 million of revenue from the Genentech Agreement, respectively. At September 30, 2021, the Company recorded a contract asset in the amount of $4.3 million, which is classified as a current asset, on the condensed consolidated balance sheet. The contract asset relates to the amount of revenue recognized for which the right to payment is contingent upon conditions other than the passage of time, such as the completion of future milestone activities.

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2021
Stockholders Equity Note [Abstract]
Common Stock	7. Common Stock The Company issued restricted shares of common stock to its founders and non-employees. In addition, the Company issued restricted shares of common stock upon the early exercise of stock options under the Company’s 2016 Stock Option and Grant Plan (the “2016 Stock Plan”). The restrictions on the common shares generally lapse over four years. The Company included the proceeds from the sale of the restricted shares of common stock as a restricted stock liability on the accompanying condensed consolidated balance sheets. Amounts are reclassified to additional paid-in capital as the restrictions lapse. The Company has the right to repurchase any unvested shares of restricted common stock at the original cost in the event of termination. At-the-Market Offering In August 2021, the Company entered into a sales agreement (the “Sales Agreement”) with Cowen and Company, LLC (“Cowen”) pursuant to which the Company may offer and sell shares of its common stock having aggregate gross proceeds of up to $300.0 million from time to time in “at-the-market” offerings through Cowen, as the Company’s sales agent. The Company agreed to pay Cowen a commission of up to 3.0% of the gross proceeds of any shares sold by Cowen under the Sales Agreement. There have been no shares of common stock sold under the Sales Agreement through September 30, 2021.

Share-Based Payments

Share-Based Payments	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Payments	8. Share-Based Payments In 2016, the Company adopted the 2016 Stock Plan. On July 8, 2020, the Company’s stockholders approved the 2020 Stock Option and Incentive Plan (the “2020 Stock Plan”), which became effective on the date immediately prior to the effectiveness of the Company’s registration statement on Form S-1 for its IPO. The 2020 Stock Plan provides for the issuance of up to 8,376,080 of share-based awards. Subsequent to July 20, 2020, no further awards will be made under the 2016 Stock Plan and all future equity-based awards are granted under the 2020 Stock Plan. To the extent outstanding options granted under the 2016 Plan are cancelled, forfeited or otherwise terminated without being exercised and would otherwise have been returned to the share reserve under the 2016 Plan, the number of shares underlying such awards will be available for future grant under the 2020 Stock Plan. All of the Company’s employees, officers, directors and consultants are eligible to be granted options, restricted stock units and other stock-based awards under the terms of the 2020 Stock Plan. There were 9,770,520 share-based awards available for grant at September 30, 2021. In July 2020, the Company adopted an Employee Stock Purchase Plan (“ESPP”) that permits eligible employees to enroll in six-month offering periods. Participants may purchase shares of the Company’s common stock, through payroll deductions, at a price equal to 85% of the fair market value of the common stock on the first or last day of the applicable six-month offering period, whichever is lower. Purchase dates under the ESPP occur on or about June 30 and December 31 each year, with the initial such purchase date under the ESPP set at December 31, 2021. In connection therewith, the Company’s shareholders authorized 1,092,532 shares for issuance pursuant to the ESPP, which is subject to annual increases to be added on the first day of each fiscal year, commencing on January 1, 2021, equal to the lesser of 2,185,064 shares of the Company’s common stock, 1% of the number of outstanding shares on the immediately preceding December 31, or an amount determined by the Board. Stock-based compensation expense included in the Company’s condensed consolidated statements of operations and comprehensive loss is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development expenses $ 6,124 $ 5,367 $ 20,420 $ 8,205 General and administrative expenses 6,294 6,562 $ 17,816 9,211 $ 12,418 $ 11,929 $ 38,236 $ 17,416

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	9. Net Loss Per Share The following table summarizes the computation of basic and diluted net loss per share of the Company: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ (60,833 ) $ (36,078 ) $ (296,416 ) $ (87,688 ) Deemed dividend resulting from extinguishment upon modification of series C preferred stock $ — $ (177,789 ) $ — $ (177,789 ) Net loss attributable to common shareholders $ (60,833 ) $ (213,867 ) $ (296,416 ) $ (265,477 ) Net loss per share, basic and diluted $ (0.66 ) $ (3.00 ) $ (3.20 ) $ (9.92 ) Weighted average shares of common stock, basic and diluted 92,692,515 71,248,846 92,599,781 26,766,687 The Company’s potentially dilutive securities, which include options to purchase common stock, restricted stock units and unvested restricted stock, have been excluded 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 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 for the periods indicated because including them would have had an anti-dilutive effect: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Options to purchase common stock 8,936,107 7,461,779 8,936,107 7,461,779 Restricted stock units 608,336 — 608,336 — Unvested restricted stock — 173,818 — 173,818 9,544,443 7,635,597 9,544,443 7,635,597

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Intellectual Property License The Company has a Collaboration and License Agreement with D. E. Shaw Research, LLC (“D. E. Shaw Research”) The Company is obligated to pay potential development milestone payments under the terms of the agreement up to $7.3 million per target, plus sales milestones and royalties, upon the achievement of certain specified contingent events. Such payments for achievement of development and regulatory milestones total up to $7.3 million in the aggregate for each of the first three products the Company develops, and up to $6.3 million in the aggregate for each product the Company develops after the first three. The Company assessed the milestone and royalty events at September 30, 2021 and concluded no such payments were due. The Company recorded research and development expense of $2.3 million and $1.9 million under this agreement for the three months ended September 30, 2021 and 2020, respectively, and $6.2 and $3.1 million for the nine months ended September 30, 2021 and 2020, respectively. At September 30, 2021 and December 31, 2020, the Company had Other Significant Arrangements The Company has certain other research and license arrangements with third parties, which provide the Company with research services with the goal of identifying and developing product candidates. The Company is obligated to pay development milestone payments for up to four targets, each in the range of $4.0 to $7.0 million, upon the achievement of certain specified contingent events. The Company assessed the milestones at September 30, 2021 and December 31, 2020, respectively, and concluded no such milestone payments were due. The Company incurred approximately $1.5 million and $0.2 million of research and development expense under these agreements for the three months ended September 30, 2021 and 2020, respectively, and $2.2 million and $1.7 million for the nine months ended September 30, 2021 and 2020, respectively. On May 26, 2021, the Company entered into a Lease (the “Lease”) with BMR-Hampshire, LLC, a Delaware limited liability company (the “Landlord”), for laboratory and office space located at 60 Hampshire Street, Cambridge, Massachusetts (the “Premises”). Under the terms of the Lease, the Company will lease approximately 41,474 square feet as the sole tenant at the Premises, which will supplement the Company’s current leased premises at 399 Binney Street, Cambridge, Massachusetts. The Landlord will contribute an aggregate of $6.2 million toward the cost of construction and tenant improvements for the Premises. In total, fixed lease payments, which include base rent, landlord fees, and parking, are $55.7 million over the lease term. The Company’s obligation to pay rent under the Lease will start on a date set forth in an estimated construction schedule pursuant to the Lease or the date on which the Landlord tenders possession of the Premises to the Company with the tenant improvements substantially completed, whichever occurs later (the “Rent Commencement Date”). The term of the Lease is ten years following the Rent Commencement Date, which is currently expected in 2022. The Company did not control the space or any of the assets being constructed therein as of September 30, 2021 and further concluded the improvements being constructed therein are the landlord’s assets with alternative use to future tenants. As such, no right of use asset or lease liability was recorded on the condensed consolidated balance sheet at September 30, 2021, since lease commencement, for accounting purposes, had not been triggered. The Company continues to lease approximately 46,631 square feet of laboratory and office space at 399 Binney Street, Cambridge, Massachusetts that currently serves as the Company’s corporate headquarters under a facility lease agreement which has a term through April 2029, subject to certain renewal options.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	11. Subsequent Events In preparing the consolidated interim financial statements as of September 30, 2021 and for the three and nine month periods then ended, the Company evaluated subsequent events for recognition and measurement purposes. The Company concluded that no events or transactions have occurred that require disclosure in the accompanying consolidated financial statements, except the following. In October 2021, the Company completed a public offering of 15,188,679 shares of common stock, including the exercise in full of the underwriters’ option to purchase an additional 1,981,132 shares, at an offering price of $26.50 per share. The Company received estimated net proceeds of $381.9 million, after deducting underwriting discounts and commissions and other estimated offering expenses.

Significant Accounting Policies

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) for interim information and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for reporting on Form 10-Q. The Company’s condensed consolidated financial statements include the accounts of Relay Therapeutics, Inc. and its wholly-owned subsidiaries, Relay Therapeutics Securities Corporation and Relay ML Discovery, LLC. All intercompany balances and transactions have been eliminated.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed consolidated balance sheet as of September 30, 2021 , the condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2021 and 2020, the condensed consolidated statements of stockholders’ equity (deficit) for the three and nine months ended September 30, 2021 and 2020, and the condensed consolidated statements of cash flows for the nine months ended September 30, 2021 and 20 20 are unaudited. The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s condensed consolidated financial position as of September 30, 2021 , the condensed consolidated results of its operations for the three and nine months ended September 30, 2021 and 2020 and cash flows for the nine months ended September 30, 2021 and 20 2 0 . The condensed consolidated financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2021 and 20 20 are unaudited. The condensed consolidated results for the three and nine months ended September 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 202 1 , any other interim periods, or any future year or period.
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 condensed consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual of research and development and manufacturing expenses, the valuation of equity instruments, the determination of the transaction price and standalone selling price of performance obligations under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, including expenses, clinical trials and research and development costs, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19, as well as the economic impact on local, regional, national and international markets. The Company has made estimates of the impact of COVID-19 within its financial statements and there may be changes to those estimates in future periods. Actual results could differ from the Company’s estimates.
Collaboration Agreements	Collaboration Agreements The Company enters into collaborative agreements with third parties to research, develop and commercialize drug candidates, pursuant to which the risks and rewards for such activities are shared between the parties. Such arrangements also provide for cost sharing between the parties during the research and development phase, as well as potential future profit share payments during the commercialization phase. In general, such contracts are evaluated under the provisions of FASB ASC 808, Collaborative Arrangements
Acquired In-Process Research and Development	Acquired In-Process Research and Development In an asset acquisition, the cost allocated to acquire in-process research and development (“IPR&D”) with no alternative future use is charged to expense at the acquisition date. Refer to Note 5, Acquisition of ZebiAI, for a more detailed description of the accounting policies applied to the recent asset acquisition.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Effective January 1, 2021, the Company adopted FASB Accounting Standards Update (“ASU”) No. 2020-06, Debt – Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity’s Own Equity Effective January 1, 2021, the Company adopted ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments the Company is based on an incurred losses model. For available-for-sale debt securities with expected credit losses, this standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. The Company will become a large accelerated filer for the fiscal year ending December 31, 2022 and, therefore, be required to adopt th is standard on January 1, 2022. The Company is assessing the impact of ASU 20 16 - 13 on the condensed consolidated financial statements and disclosures and does not expect it to have a material impact on the Company’s condensed consolidated financial statements or disclosures . From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that the Company adopts as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected to use the extended transition period related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different effective dates for public and nonpublic companies, the Company can adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and can do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. As noted above, the Company will become a large accelerated filer for the fiscal year ending December 31, 2021, and as such it will lose emerging growth status as of that date.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis and Level of the Fair Value Hierarchy	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of September 30, 2021: Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 216,195 $ — $ — $ 216,195 Investments: US treasury bills — 256,668 — 256,668 US agency securities — 131,281 — 131,281 Total investments — 387,949 — 387,949 Total assets $ 216,195 $ 387,949 $ — $ 604,144 Liabilities Contingent consideration — — 45,465 45,465 Total liabilities $ — $ — $ 45,465 $ 45,465 Fair Value Measurements as of December 31, 2020: Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 447,146 $ — $ — $ 447,146 Investments: US treasury bills — 33,026 — 33,026 US agency securities — 197,389 — 197,389 Total investments — 230,415 — 230,415 Total $ 447,146 $ 230,415 $ — $ 677,561
Schedule of Changes in Fair Value of Contingent Consideration Liability	The following table reconciles the change in fair value of the contingent consideration liability based on level 3 inputs (in thousands): Nine Months Ended September 30, 2021 Balance at December 31, 2020 $ — Contingent consideration related to acquisition of ZebiAI 43,465 Increase in fair value of contingent payments 2,000 Balance at September 30, 2021 $ 45,465

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Schedule Of Investments [Abstract]
Summary of Fair Value of Available-for-Sale Investments by Type of Security	The fair value of available-for-sale investments by type of security was as follows: September 30, 2021 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Investments: U.S treasury bills $ 117,993 $ 13 $ — $ 118,006 U.S agency securities 29,497 1 — 29,498 Total investments with a maturity of one year or less 147,490 14 — 147,504 U.S treasury bills 138,675 — (13 ) 138,662 U.S agency securities 101,774 9 — 101,783 Total investments with a maturity of one to two years 240,449 9 (13 ) 240,445 Total investments $ 387,939 $ 23 $ (13 ) $ 387,949 December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Investments: U.S treasury bills $ 29,997 $ 21 $ — $ 30,018 U.S agency securities 20,996 5 — 21,001 Total investments with a maturity of one year or less 50,993 26 — 51,019 U.S treasury bills 3,008 — — 3,008 U.S agency securities 176,350 38 — 176,388 Total investments with a maturity of one to two years 179,358 38 — 179,396 Total investments $ 230,351 $ 64 $ — $ 230,415

Acquisition of ZebiAI (Tables)

Acquisition of ZebiAI (Tables)	9 Months Ended
	Sep. 30, 2021
Business Combination Description [Abstract]
Summary of Net Assets Acquired Based on Estimated Fair Values	The following table summarizes the net assets acquired based on their estimated fair values as of the Acquisition Date (in thousands): Acquired IPR&D asset $ 123,000 Loss on initial consolidation of VIE 11,855 Assets obtained in asset acquisition 662 Liabilities assumed in asset acquisition (2,330 ) Intangible asset 2,300 Net acquired assets $ 135,487

Share-Based Payments (Tables)

Share-Based Payments (Tables)	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock-Based Compensation Expense Included In The Company's Condensed Consolidated Statements of Operations And Comprehensive Loss	Stock-based compensation expense included in the Company’s condensed consolidated statements of operations and comprehensive loss is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Research and development expenses $ 6,124 $ 5,367 $ 20,420 $ 8,205 General and administrative expenses 6,294 6,562 $ 17,816 9,211 $ 12,418 $ 11,929 $ 38,236 $ 17,416

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Summary of Computation of Basic and Diluted Net Loss Per Share	The following table summarizes the computation of basic and diluted net loss per share of the Company: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net loss $ (60,833 ) $ (36,078 ) $ (296,416 ) $ (87,688 ) Deemed dividend resulting from extinguishment upon modification of series C preferred stock $ — $ (177,789 ) $ — $ (177,789 ) Net loss attributable to common shareholders $ (60,833 ) $ (213,867 ) $ (296,416 ) $ (265,477 ) Net loss per share, basic and diluted $ (0.66 ) $ (3.00 ) $ (3.20 ) $ (9.92 ) Weighted average shares of common stock, basic and diluted 92,692,515 71,248,846 92,599,781 26,766,687
Summary of Antidilutive Securities Excluded From Computation of Earnings Per Share	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 for the periods indicated because including them would have had an anti-dilutive effect: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Options to purchase common stock 8,936,107 7,461,779 8,936,107 7,461,779 Restricted stock units 608,336 — 608,336 — Unvested restricted stock — 173,818 — 173,818 9,544,443 7,635,597 9,544,443 7,635,597

Nature of Business and Basis _2

Nature of Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ 700,644	$ 404,228

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis and Level of the Fair Value Hierarchy (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Liabilities
Contingent consideration liability	$ 50,465
Fair value on a recurring basis [Member]
Investments:
Total assets	604,144	$ 677,561
Liabilities
Contingent consideration liability	45,465
Total liabilities	45,465
Investments [Member] | Fair value on a recurring basis [Member]
Investments:
Total investments	387,949	230,415
Investments [Member] | Fair value on a recurring basis [Member] | US treasury bills [Member]
Investments:
Total investments	256,668	33,026
Investments [Member] | Fair value on a recurring basis [Member] | US agency securities [Member]
Investments:
Total investments	131,281	197,389
Cash equivalents [Member] | Fair value on a recurring basis [Member] | Money market funds [Member]
Cash equivalents:
Assets, fair value	216,195	447,146
Level 1 [Member] | Fair value on a recurring basis [Member]
Investments:
Total assets	216,195	447,146
Level 1 [Member] | Cash equivalents [Member] | Fair value on a recurring basis [Member] | Money market funds [Member]
Cash equivalents:
Assets, fair value	216,195	447,146
Level 2 [Member] | Fair value on a recurring basis [Member]
Investments:
Total assets	387,949	230,415
Level 2 [Member] | Investments [Member] | Fair value on a recurring basis [Member]
Investments:
Total investments	387,949	230,415
Level 2 [Member] | Investments [Member] | Fair value on a recurring basis [Member] | US treasury bills [Member]
Investments:
Total investments	256,668	33,026
Level 2 [Member] | Investments [Member] | Fair value on a recurring basis [Member] | US agency securities [Member]
Investments:
Total investments	131,281	$ 197,389
Level 3 [Member]
Liabilities
Contingent consideration liability	45,465
Level 3 [Member] | Fair value on a recurring basis [Member]
Liabilities
Contingent consideration liability	45,465
Total liabilities	$ 45,465

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - ZebiAI Therapeutics, Inc. [Member] - Level 3 [Member] - USD ($) $ in Millions	Sep. 30, 2021	Apr. 22, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Business combination contingent consideration liability, milestones payments		$ 85
Business combination contingent consideration liability, milestones payments measured	$ 45.5	43.5
Business combination contingent consideration liability, contingent earnout payments		$ 100

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Changes in Fair Value of Contingent Consideration Liability (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ending balance	$ 50,465
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration related to acquisition of ZebiAI	43,465
Increase in fair value of contingent payments	2,000
Ending balance	$ 45,465

Investments - Summary of Fair V

Investments - Summary of Fair Value of Available-for-Sale Investments by Type of Security (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 387,939	$ 230,351
Unrealized Gains	23	64
Unrealized Losses	(13)
Fair Value	387,949	230,415
Investments with a maturity of one year or less [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	147,490	50,993
Unrealized Gains	14	26
Fair Value	147,504	51,019
Investments with a maturity of one to two years [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	240,449	179,358
Unrealized Gains	9	38
Unrealized Losses	(13)
Fair Value	240,445	179,396
U.S treasury bills [Member] | Investments with a maturity of one year or less [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	117,993	29,997
Unrealized Gains	13	21
Fair Value	118,006	30,018
U.S treasury bills [Member] | Investments with a maturity of one to two years [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	138,675	3,008
Unrealized Losses	(13)
Fair Value	138,662	3,008
U.S agency securities [Member] | Investments with a maturity of one year or less [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	29,497	20,996
Unrealized Gains	1	5
Fair Value	29,498	21,001
U.S agency securities [Member] | Investments with a maturity of one to two years [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	101,774	176,350
Unrealized Gains	9	38
Fair Value	$ 101,783	$ 176,388

Acquisition of ZebiAI - Additio

Acquisition of ZebiAI - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Apr. 22, 2021	Sep. 30, 2021
Business Acquisition [Line Items]
Fair value of contingent milestone payments		$ 50,465
ZebiAI Therapeutics, Inc. [Member]
Business Acquisition [Line Items]
Acquisition date	Apr. 22, 2021
Upfront consideration payable	$ 20,000
Aggregate fair value consideration transferred	60,800
Milestone payments	$ 85,000
Percentage of payment related to collaboration or other agreements	10.00%
Payment related to collaboration or other agreements	$ 100,000
Consideration transferred	135,500
Loss on initial consolidation of VIE	11,855
Stock-based compensation expense associated with accelerated vesting for certain stock options		$ 4,600
Fair value of contingent milestone payments	$ 48,500
Number of shares that would be issued upon milestone achievement		2,414,498
Average share value of 5-day		$ 35.20
Contingent consideration payment description		The Contingent Milestone Payments are payable in common shares based on a fixed amount assigned to each milestone and the weighted average share price of the Company’s stock for the 5-day period prior to the milestone achievement.
ZebiAI Therapeutics, Inc. [Member] | General and Administrative Expense [Member]
Business Acquisition [Line Items]
Acquisition-related costs		$ 900
Common Stock [Member] | ZebiAI Therapeutics, Inc. [Member]
Business Acquisition [Line Items]
Issued shares of common stock	1,883,487

Acquisition of ZebiAI - Summary

Acquisition of ZebiAI - Summary of Net Assets Acquired Based on Estimated Fair Values (Detail) - ZebiAI Therapeutics, Inc. [Member] $ in Thousands	Apr. 22, 2021USD ($)
Business Acquisition [Line Items]
Acquired IPR&D asset	$ 123,000
Loss on initial consolidation of VIE	11,855
Assets obtained in asset acquisition	662
Liabilities assumed in asset acquisition	(2,330)
Intangible asset	2,300
Net acquired assets	$ 135,487

Collaboration and License Arr_2

Collaboration and License Arrangements - Additional Information (Detail) - USD ($)	May 13, 2021	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Collaboration And License Arrangement [Line Items]
Collaboration revenue		$ 666,000		$ 2,462,000
Contract asset		4,251,000		$ 4,251,000	$ 7,654,000
EQRx, Inc [Member]
Collaboration And License Arrangement [Line Items]
Collaborative arrangement, purpose				In August 2021, the Company and EQRx, Inc. (“EQRx”), a related party, entered into the Discovery Collaboration Agreement (“Collaboration Agreement”) to discover, develop, and commercialize novel medicines against validated oncology targets.
Collaborative arrangement, rights and obligations				In August 2021, the Company and EQRx, Inc. (“EQRx”), a related party, entered into the Discovery Collaboration Agreement (“Collaboration Agreement”) to discover, develop, and commercialize novel medicines against validated oncology targets. Under the terms of the Collaboration Agreement, the Company is responsible for the discovery phase through to filing of the application for an Investigational New Drug (“IND”), while EQRx is responsible for clinical development, regulatory and commercialization of the product candidates under the collaboration. Subject to certain opt-out rights, the Company and EQRx share equally in the discovery, development and commercialization costs, as well as the net profits and losses from sales of any collaboration medicines, if approved. The Company retains the right to develop any collaboration medicines in combination with its wholly-owned pipeline.
Genentech [Member] | Genentech Agreement [Member]
Collaboration And License Arrangement [Line Items]
Collaborative arrangement, purpose				On December 11, 2020, the Company entered into the Genentech Agreement, which granted Genentech a license to develop and commercialize RLY-1971
Collaborative arrangement, rights and obligations				. RLY-1971 is currently being developed in a Phase 1a clinical trial for patients with advanced solid tumors (the “Phase 1a Trial”). Unless Genentech elects to exercise its option to conduct the remainder of the ongoing Phase 1a Trial, the Company is responsible for the completion of this trial. Genentech is responsible for conducting all subsequent clinical development of RLY-1971. The Company is also responsible for the one-time transfer of the active pharmaceutical ingredient (“API”) and other materials related to RLY-1971 to Genentech.
Non-refundable upfront payment				$ 75,000,000
Non-refundable milestone payment transfer amount	$ 5,000,000
Milestone payment receivable				20,000,000
Maximum additional amount received upon milestone achievement				695,000,000
Collaboration agreement transaction price				86,300,000
Non-refundable milestone payment for completion amount				5,000,000
Variable consideration related to reimbursements due for research and development services				1,300,000
Development based milestone payments under agreement				0
Regulatory based milestone payments under agreement				0
Collaboration revenue		400,000		2,100,000
Genentech [Member] | Genentech Agreement [Member] | Research and Development Services [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue		400,000		1,400,000
Genentech [Member] | Genentech Agreement [Member] | Transfer of Active Pharmaceutical Ingredients [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue			$ 400,000		$ 0
Contract asset		4,300,000		4,300,000
Genentech [Member] | Genentech Agreement [Member] | Stand-alone Selling Prices (“SSP”) [Member]
Collaboration And License Arrangement [Line Items]
Collaboration agreement transaction price				86,300,000
Genentech [Member] | Genentech Agreement [Member] | Stand-alone Selling Prices (“SSP”) [Member] | Transfer of License [Member]
Collaboration And License Arrangement [Line Items]
Remaining performance obligations		82,900,000		82,900,000
Genentech [Member] | Genentech Agreement [Member] | Stand-alone Selling Prices (“SSP”) [Member] | Research and Development Services [Member]
Collaboration And License Arrangement [Line Items]
Remaining performance obligations		3,000,000		3,000,000
Genentech [Member] | Genentech Agreement [Member] | Stand-alone Selling Prices (“SSP”) [Member] | Transfer of Active Pharmaceutical Ingredients [Member]
Collaboration And License Arrangement [Line Items]
Remaining performance obligations		$ 400,000		400,000
Genentech [Member] | Genentech Agreement [Member] | Outside US [Member]
Collaboration And License Arrangement [Line Items]
Maximum additional amount received upon milestone achievement				$ 410,000,000

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Aug. 31, 2021	Sep. 30, 2020	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock Restriction Period			4 years
Maximum [Member] | Sales Agreement [Member] | Cowen [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of commission of shares sold	3.00%
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares sold		23,000,000
Common Stock [Member] | Sales Agreement [Member] | Cowen [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate gross proceeds from the sale of shares	$ 300
Common stock shares sold			0

Share-Based Payments - Addition

Share-Based Payments - Additional Information (Detail) - shares	Jan. 01, 2021	Jul. 31, 2021	Sep. 30, 2021	Jul. 08, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Award, Number of Shares Authorized			9,770,520	8,376,080
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Award, Number of Shares Authorized		1,092,532
Percentage of fair market value of common stock		85.00%
Shares authorized additionally under ESPP	2,185,064
Percentage of additional common stock authorized		1.00%

Share-Based Payments - Schedule

Share-Based Payments - Schedule of Stock-Based Compensation Expense Included In The Company's Condensed Consolidated Statements of Operations And Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 12,418	$ 11,929	$ 38,236	$ 17,416
Research and development expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	6,124	5,367	20,420	8,205
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 6,294	$ 6,562	$ 17,816	$ 9,211

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (60,833)	$ (193,399)	$ (42,184)	$ (36,078)	$ (26,724)	$ (24,886)	$ (296,416)	$ (87,688)
Deemed dividend resulting from extinguishment upon modification of series C preferred stock				(177,789)				(177,789)
Net loss attributable to common stockholders	$ (60,833)			$ (213,867)			$ (296,416)	$ (265,477)
Net loss per share, basic and diluted	$ (0.66)			$ (3)			$ (3.20)	$ (9.92)
Weighted average shares of common stock, basic and diluted	92,692,515			71,248,846			92,599,781	26,766,687

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Antidilutive Securities Excluded From Computation of Earnings Per Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect	9,544,443	7,635,597	9,544,443	7,635,597
Options to purchase common stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect	8,936,107	7,461,779	8,936,107	7,461,779
Restricted stock units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect	608,336		608,336
Unvested restricted stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect		173,818		173,818

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	May 26, 2021USD ($)ft²	Jun. 15, 2020USD ($)	Sep. 30, 2021USD ($)ft²Targetshares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)ft²Targetshares	Sep. 30, 2020USD ($)	Aug. 16, 2021USD ($)	May 12, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019shares
Commitments and Contingencies Disclosure [Line Items]
Accrued expenses			$ 20,102,000		$ 20,102,000				$ 5,760,000
Area of land | ft²			46,631		46,631
Right of use asset			$ 21,239,000		$ 21,239,000				22,579,000
Letter of credit			1,700,000		$ 1,700,000
Letter of credit expiration date					Aug. 31, 2033
DE Shaw Research [Member]
Commitments and Contingencies Disclosure [Line Items]
Research and development expense			2,300,000	$ 1,900,000	$ 6,200,000	$ 3,100,000
Accrued expenses			0		0				1,500,000
Prepaid balance			$ 6,700,000		$ 6,700,000				0
DE Shaw Research [Member] | License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Outstanding convertible preferred stock converted into common shares | shares			3,281,253		3,281,253
Research and development arrangement, term of contract					3 years
Research and development arrangement, annual fee		$ 7,900,000	$ 1,000,000		$ 1,000,000		$ 9,900,000	$ 7,900,000
Research and development arrangement, expiration date		Aug. 16, 2025
Milestone payment Due			7,300,000		7,300,000
Maximum additional amount received upon milestone achievement					6,300,000
DE Shaw Research [Member] | Lease Agreement
Commitments and Contingencies Disclosure [Line Items]
Milestone payment Due			0		0
Other Third Parties [Member]
Commitments and Contingencies Disclosure [Line Items]
Research and development expense			1,500,000	$ 200,000	2,200,000	$ 1,700,000
Other Third Parties [Member] | License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Milestone payment Due			$ 0		$ 0				$ 0
Number of milestone targets | Target			4		4
BMR Hampshire, LLC [Member]
Commitments and Contingencies Disclosure [Line Items]
Area of land | ft²	41,474
Fixed lease payments					$ 55,700,000
Contribution toward the cost of construction and tenant improvements for the premises	$ 6,200,000
Term of the lease			10 years		10 years
Right of use asset			$ 0		$ 0
Maximum [Member] | DE Shaw Research [Member] | License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Agreement renewal period					1 year
Potential development milestone payments					$ 7,300,000
Maximum [Member] | Other Third Parties [Member] | License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Potential development milestone payments					7,000,000
Minimum [Member] | Other Third Parties [Member] | License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Potential development milestone payments					$ 4,000,000
Series A Preferred Stock [Member] | DE Shaw Research [Member] | License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Shares held | shares										9,999,999
Series C Preferred Stock [Member] | DE Shaw Research [Member] | License Agreement Terms [Member]
Commitments and Contingencies Disclosure [Line Items]
Shares held | shares										1,557,875

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Oct. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Subsequent Event [Line Items]
Proceeds from issuance of shares			$ 4,078	$ 1,160
Common Stock [Member]
Subsequent Event [Line Items]
Common stock shares sold		23,000,000
Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Common stock shares sold	15,188,679
Additional shares issued	1,981,132
Shares issue price per share	$ 26.50
Proceeds from issuance of shares	$ 381,900