Relay Therapeutics (RLAY) 10-Q 12 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 10, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
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		92,695,097
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	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 260,069	$ 447,646
Investments	411,151	230,415
Accounts receivable	279	75,000
Contract asset	4,193	7,654
Prepaid expenses and other current assets	5,584	9,385
Total current assets	681,276	770,100
Property and equipment, net	6,559	6,250
Operating lease assets	21,688	22,579
Restricted cash	2,578	878
Intangible asset	2,300
Other assets		22
Total assets	714,401	799,829
Current liabilities:
Accounts payable	7,871	6,351
Accrued expenses and other current liabilities	15,405	5,760
Operating lease liabilities	1,695	1,521
Deferred revenue	414
Total current liabilities	25,385	13,632
Operating lease liabilities, net of current portion	22,022	22,901
Restricted stock liability		3
Contingent consideration liability	48,465
Total liabilities	95,872	36,536
Commitments and contingencies (Note 10)
Stockholders’ equity:
Common stock, $0.001 par value; 150,000,000 shares authorized at June 30, 2021 and December 31, 2020; 92,552,645 and 89,991,324 shares issued at June 30, 2021 and December 31, 2020, respectively; 92,552,645 and 89,906,835 shares outstanding at June 30, 2021 and December 31, 2020, respectively	92	90
Additional paid-in capital	1,258,312	1,167,367
Accumulated other comprehensive income (loss)	(64)	64
Accumulated deficit	(639,811)	(404,228)
Total stockholders’ equity	618,529	763,293
Total liabilities and stockholders’ equity	$ 714,401	$ 799,829

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 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	92,552,645	89,991,324
Common stock shares outstanding	92,552,645	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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Collaboration revenue	$ 844		$ 1,796
Revenue from Contract with Customer, Product and Service [Extensible List]	rlay:CollaborationRevenueMember	rlay:CollaborationRevenueMember	rlay:CollaborationRevenueMember	rlay:CollaborationRevenueMember
Total revenue	$ 844		$ 1,796
Operating expenses:
Research and development expenses	45,147	$ 21,666	75,769	$ 43,363
In-process research and development expenses	123,000		123,000
Loss on initial consolidation of variable interest entity	11,855		11,855
General and administrative expenses	14,422	6,053	27,156	10,814
Total operating expenses	194,424	27,719	237,780	54,177
Loss from operations	(193,580)	(27,719)	(235,984)	(54,177)
Other income (expense):
Interest income	180	998	406	2,570
Other income (expense)	1	(3)	(4)	(3)
Total other income (expense), net	181	995	402	2,567
Net loss	$ (193,399)	$ (26,724)	$ (235,582)	$ (51,610)
Net loss per share, basic and diluted	$ (2.10)	$ (6.06)	$ (2.58)	$ (12.06)
Weighted average shares of common stock, basic and diluted	91,939,439	4,408,470	91,188,160	4,281,169
Other comprehensive (loss) income:
Unrealized holding (loss) gain	$ (76)	$ (763)	$ (128)	$ 306
Total other comprehensive (loss) income	(76)	(763)	(128)	306
Total comprehensive loss	$ (193,475)	$ (27,487)	$ (235,710)	$ (51,304)

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	(51,610)
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
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
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	(235,582)
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
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

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (235,582)	$ (51,610)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Stock-based compensation expense	25,818	5,487
Depreciation expense	1,879	1,724
Net amortization of premiums and discounts on investments	701	(438)
Acquired in-process research and development	123,000
Loss on initial consolidation of variable interest entity	11,855
Changes in assets and liabilities:
Prepaid expenses and other current assets	4,964	1,061
Lease assets and liabilities, net	186	192
Accounts payable	(867)	(4,045)
Accrued expenses and other liabilities	8,261	4,451
Accounts receivable	74,801
Contract asset	3,462
Other assets	22
Net cash provided by (used in) operating activities	18,500	(43,178)
Cash flows from investing activities:
Purchases of property and equipment	(855)	(1,434)
Purchases of investments	(646,239)	(71,103)
Proceeds from maturities of investments	464,673	210,556
Cash paid for acquisition of ZebiAI, net of cash acquired	(25,132)
Net cash provided by (used in) investing activities	(207,553)	138,019
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	3,176	718
Payment of deferred offering costs		(460)
Net cash provided by financing activities	3,176	258
Net (decrease) increase in cash, cash equivalents and restricted cash	(185,877)	95,099
Cash, cash equivalents and restricted cash at beginning of period	448,524	42,832
Cash, cash equivalents and restricted cash at end of period	262,647	137,931
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment additions included in accounts payable and accrued expenses	1,077	330
Reclassification of restricted stock liability to additional paid-in capital	3	144
Deferred offering costs included in accounts payable and accrued expenses		$ 664
Assets obtained in asset acquisition	662
Liabilities assumed in asset acquisition	2,330
Fair value of equity issued in connection with asset acquisition	$ 61,948

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Restricted Cash And Cash Equivalents At Carrying Value [Abstract]
Cash and cash equivalents	$ 260,069	$ 447,646	$ 137,053
Restricted cash	2,578	878	878
Total cash, cash equivalents and restricted cash as shown on condensed consolidated statements of cash flows	$ 262,647	$ 448,524	$ 137,931	$ 42,832

Nature of Business and Basis of

Nature of Business and Basis of Presentation	6 Months Ended
	Jun. 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 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 to effectively drug protein targets that have previously been intractable. The Company’s initial focus is on enhancing small molecule therapeutic discovery in targeted oncology and genetic disease. 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 7. 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 $639,811

Significant Accounting Policie

Significant Accounting Policies	6 Months Ended
	Jun. 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 June 30, 2021, the condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2021 and 2020, the condensed consolidated statements of stockholders’ equity (deficit) for the three and six months ended June 30, 2021 and 2020, and the condensed consolidated statements of cash flows for the six months ended June 30, 202 1 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 June 30, 202 1 , the condensed consolidated results of its operations for the three and six months ended June 30, 2021 and 2020 and cash flows for the six months ended June 30, 202 1 and 20 2 0 . The condensed consolidated financial data and other information disclosed in these notes related to the three and six months ended June 30, 202 1 and 20 20 are unaudited. The condensed consolidated results for the three and six months ended June 30, 202 1 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 Accounting Standards Codification 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. 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 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 Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In November 2019, the FASB subsequently issued ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates 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. The Company will become a large accelerated filer for the fiscal year ending December 31, 2022, and as such it will lose emerging growth status on December 31, 2021.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 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 June 30, 2021: Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 247,749 $ — $ — $ 247,749 Investments: US treasury bills — 252,793 — 252,793 US agency securities — 158,358 — 158,358 Total investments — 411,151 — 411,151 Total assets $ 247,749 $ 411,151 $ — $ 658,900 Liabilities Contingent consideration — — 43,465 43,465 Total liabilities $ — $ — $ 43,465 $ 43,465 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. 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 ASC 480 Distinguishing Liabilities from Equity (“ASC 480”) (Refer to Note 5). Due to the uncertainties associated with the development of platforms and drug candidates in the pharmaceutical industry and the effects of changes in other assumptions including probability of success, the Company expects its estimates regarding the fair value of Contingent Milestone Payments to change in the future, 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.

Investments

Investments	6 Months Ended
	Jun. 30, 2021
Schedule Of Investments [Abstract]
Investments	4. Investments The fair value of available-for-sale investments by type of security was as follows: June 30, 2021 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Investments: U.S treasury bills $ 68,162 $ 4 $ — $ 68,166 U.S agency securities 12,999 2 13,001 Total investments with a maturity of one year or less 81,161 6 — 81,167 U.S treasury bills 184,707 — (80 ) 184,627 U.S agency securities 145,347 10 145,357 Total investments with a maturity of one to two years 330,054 10 (80 ) 329,984 Total investments $ 411,215 $ 16 $ (80 ) $ 411,151 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	6 Months Ended
	Jun. 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 $20,000 in cash and issued 1,883,487 shares of the Company’s common stock at an aggregate fair value of $60,800. In addition, (i) the ZebiAI Holders will be eligible to receive up to an additional $85,000 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 $100,000, 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 . . 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 three and six months ended June 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. 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 $48,465. 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). There were no adjustments to the fair value of the Contingent Milestone Payments as of June 30, 2021. 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. Accordingly, the number of shares to be issued upon a milestone achievement vary dependent on the Company’s stock price. The settlement amounts of Contingent Milestone Payments are predominantly fixed. If the milestones were achieved in full on June 30, 2021, the number of shares to be issued would be 2,351,314 based on a weighted average per share price of $36.15 for the 5-day period prior to June 30, 2021. The Contingent Earnout Payments were not accounted for as derivatives under ASC 815 Derivatives and Hedging

Collaboration and License Arran

Collaboration and License Arrangement with Genentech	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Arrangement with Genentech	6. Collaboration and License Arrangement with Genentech 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 $75,000, 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 Investigational New Drug ("IND") application for RLY-1971 to Genentech upon which the Company received payment for the associated non-refundable milestone payment of $5,000 in May 2021. The Company is eligible to receive up to $20,000 in additional near-term milestone payments. The Company is also eligible to receive up to an aggregate of an additional $695,000 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 $410,000 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 $86,134, which includes both fixed and variable consideration amounts. The total transaction price of $86,134 is comprised of (i) the $75,000 fixed, non-refundable upfront payment, (ii) a $5,000 non-refundable milestone payment due upon the transfer of the IND application Allocation of Transaction Price to Performance Obligations The Company allocated the transaction price of $86,134 based on the stand-alone selling prices (“SSP”) of each of the performance obligations as follows: • $82,512 million for the transfer of the license • $2,891 million for research and development services; and • $317 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 six months ended June 30, 2021 related to the R&D services amount s to $ 386 and $ 1,164 , 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 $317. There was no revenue recognized related to this performance obligation during the year ended December 31, 2020. During the three and six months ended June 30, 2021 the Company recognized an aggregate of $786 and $1,738 of revenue from the Genentech Agreement, respectively. At June 30, 2021, the Company recorded a contract asset in the amount of $4,193, 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	6 Months Ended
	Jun. 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.

Share-Based Payments

Share-Based Payments	6 Months Ended
	Jun. 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 10,653,994 share-based awards available for grant at June 30, 2021. Stock-based compensation expense included in the Company’s condensed consolidated statements of operations and comprehensive loss is as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Research and development expenses $ 10,145 $ 1,941 $ 14,296 $ 2,838 General and administrative expenses 6,002 2,091 $ 11,522 2,649 $ 16,147 $ 4,032 $ 25,818 $ 5,487 As of June 30, 2021, total unrecognized compensation cost related to the unvested stock options was $132,744, which is expected to be recognized over a weighted average period of 2.71 years.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 Net loss $ (193,399 ) $ (26,724 ) $ (235,582 ) $ (51,610 ) Net loss per share, basic and diluted $ (2.10 ) $ (6.06 ) $ (2.58 ) $ (12.06 ) Weighted average shares of common stock, basic and diluted 91,939,439 4,408,470 91,188,160 4,281,169 The Company’s potentially dilutive securities, which include Convertible Preferred Stock (prior to the IPO), 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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 Convertible preferred stock — 59,883,877 — 59,883,877 Options to purchase common stock 8,906,194 7,471,087 8,906,194 7,471,087 Restricted stock units 505,393 290,477 505,393 290,477 Unvested restricted stock — 290,477 — 290,477 9,411,587 67,935,918 9,411,587 67,935,918

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 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 $7,300 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 $7,250 in the aggregate for each of the first three products the Company develops, and up to $6,250 in the aggregate for each product the Company develops after the first three. The Company assessed the milestone and royalty events at June 30, 2021 and concluded no such payments were due. The Company recorded research and development expense of $2,096 and $974 under this agreement for the three months ended June 30, 2021 and 2020, respectively, and $3,941 and $1,224 for the six months ended June 30, 2021, and 2020, respectively. At June 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 $4,000 to $7,000, upon the achievement of certain specified contingent events. The Company assessed the milestones at June 30, 2021 and December 31, 2020, respectively, and concluded no such milestone payments were due. The Company incurred approximately $703 and $236 of research and development expense under these agreements for the three months ended June 30, 2021 and 2020, respectively, and $1,105 and $1,430 for the six months ended June 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 $6,221 million toward the cost of construction and tenant improvements for the Premises. 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. The Company did not control the space as of June 30, 2021 and as such, no right of use asset was recorded on the condensed consolidated balance sheet. 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	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	11. Subsequent Events In preparing the consolidated interim financial statements as of June 30, 2021 and for the three and six 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 August 2021, the Company and EQRx, Inc. (“EQRx”), a related party, entered into a discovery collaboration agreement to discover, develop, and commercialize novel medicines against validated oncology targets. Under the terms of the agreement, the Company will be responsible for the discovery phase through to Investigational New Drug application filing, while EQRx will be responsible for clinical development, regulatory and commercialization efforts of the product candidates developed pursuant to the collaboration. Subject to certain opt-out rights, the Company and EQRx will equally share in the discovery, development and commercialization costs and the net profits 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.

Significant Accounting Policies

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 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 June 30, 2021, the condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2021 and 2020, the condensed consolidated statements of stockholders’ equity (deficit) for the three and six months ended June 30, 2021 and 2020, and the condensed consolidated statements of cash flows for the six months ended June 30, 202 1 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 June 30, 202 1 , the condensed consolidated results of its operations for the three and six months ended June 30, 2021 and 2020 and cash flows for the six months ended June 30, 202 1 and 20 2 0 . The condensed consolidated financial data and other information disclosed in these notes related to the three and six months ended June 30, 202 1 and 20 20 are unaudited. The condensed consolidated results for the three and six months ended June 30, 202 1 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 Accounting Standards Codification 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.
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 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 Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In November 2019, the FASB subsequently issued ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates 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. The Company will become a large accelerated filer for the fiscal year ending December 31, 2022, and as such it will lose emerging growth status on December 31, 2021.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 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 June 30, 2021: Level 1 Level 2 Level 3 Total Assets Cash equivalents: Money market funds $ 247,749 $ — $ — $ 247,749 Investments: US treasury bills — 252,793 — 252,793 US agency securities — 158,358 — 158,358 Total investments — 411,151 — 411,151 Total assets $ 247,749 $ 411,151 $ — $ 658,900 Liabilities Contingent consideration — — 43,465 43,465 Total liabilities $ — $ — $ 43,465 $ 43,465 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

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 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: June 30, 2021 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Investments: U.S treasury bills $ 68,162 $ 4 $ — $ 68,166 U.S agency securities 12,999 2 13,001 Total investments with a maturity of one year or less 81,161 6 — 81,167 U.S treasury bills 184,707 — (80 ) 184,627 U.S agency securities 145,347 10 145,357 Total investments with a maturity of one to two years 330,054 10 (80 ) 329,984 Total investments $ 411,215 $ 16 $ (80 ) $ 411,151 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)	6 Months Ended
	Jun. 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)	6 Months Ended
	Jun. 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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 Research and development expenses $ 10,145 $ 1,941 $ 14,296 $ 2,838 General and administrative expenses 6,002 2,091 $ 11,522 2,649 $ 16,147 $ 4,032 $ 25,818 $ 5,487

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 Net loss $ (193,399 ) $ (26,724 ) $ (235,582 ) $ (51,610 ) Net loss per share, basic and diluted $ (2.10 ) $ (6.06 ) $ (2.58 ) $ (12.06 ) Weighted average shares of common stock, basic and diluted 91,939,439 4,408,470 91,188,160 4,281,169
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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 Convertible preferred stock — 59,883,877 — 59,883,877 Options to purchase common stock 8,906,194 7,471,087 8,906,194 7,471,087 Restricted stock units 505,393 290,477 505,393 290,477 Unvested restricted stock — 290,477 — 290,477 9,411,587 67,935,918 9,411,587 67,935,918

Nature of Business and Basis _2

Nature of Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ 639,811	$ 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	Jun. 30, 2021	Dec. 31, 2020
Liabilities
Contingent consideration liability	$ 48,465
Fair value on a recurring basis [Member]
Investments:
Total assets	658,900	$ 677,561
Liabilities
Contingent consideration liability	43,465
Total liabilities	43,465
Investments [Member] | Fair value on a recurring basis [Member]
Investments:
Total investments	411,151	230,415
Investments [Member] | Fair value on a recurring basis [Member] | US treasury bills [Member]
Investments:
Total investments	252,793	33,026
Investments [Member] | Fair value on a recurring basis [Member] | US agency securities [Member]
Investments:
Total investments	158,358	197,389
Cash equivalents [Member] | Fair value on a recurring basis [Member] | Money market funds [Member]
Cash equivalents:
Assets, fair value	247,749	447,146
Level 1 [Member] | Fair value on a recurring basis [Member]
Investments:
Total assets	247,749	447,146
Level 1 [Member] | Cash equivalents [Member] | Fair value on a recurring basis [Member] | Money market funds [Member]
Cash equivalents:
Assets, fair value	247,749	447,146
Level 2 [Member] | Fair value on a recurring basis [Member]
Investments:
Total assets	411,151	230,415
Level 2 [Member] | Investments [Member] | Fair value on a recurring basis [Member]
Investments:
Total investments	411,151	230,415
Level 2 [Member] | Investments [Member] | Fair value on a recurring basis [Member] | US treasury bills [Member]
Investments:
Total investments	252,793	33,026
Level 2 [Member] | Investments [Member] | Fair value on a recurring basis [Member] | US agency securities [Member]
Investments:
Total investments	158,358	$ 197,389
Level 3 [Member] | Fair value on a recurring basis [Member]
Liabilities
Contingent consideration liability	43,465
Total liabilities	$ 43,465

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - ZebiAI Therapeutics, Inc. [Member] - Level 3 [Member] $ in Millions	Apr. 22, 2021USD ($)
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	43.5
Business combination contingent consideration liability, contingent earnout payments	$ 100

Investments - Summary of Fair V

Investments - Summary of Fair Value of Available-for-Sale Investments by Type of Security (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 411,215	$ 230,351
Unrealized Gains	16	64
Unrealized Losses	(80)
Fair Value	411,151	230,415
Investments with a maturity of one year or less [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	81,161	50,993
Unrealized Gains	6	26
Fair Value	81,167	51,019
Investments with a maturity of one to two years [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	330,054	179,358
Unrealized Gains	10	38
Unrealized Losses	(80)
Fair Value	329,984	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	68,162	29,997
Unrealized Gains	4	21
Fair Value	68,166	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	184,707	3,008
Unrealized Losses	(80)
Fair Value	184,627	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	12,999	20,996
Unrealized Gains	2	5
Fair Value	13,001	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	145,347	176,350
Unrealized Gains	10	38
Fair Value	$ 145,357	$ 176,388

Acquisition of ZebiAI - Additio

Acquisition of ZebiAI - Additional Information (Detail) - USD ($)	Apr. 22, 2021	Jun. 30, 2021	Jun. 30, 2021
Business Acquisition [Line Items]
Fair value of contingent milestone payments		$ 48,465,000	$ 48,465,000
ZebiAI Therapeutics, Inc. [Member]
Business Acquisition [Line Items]
Acquisition date	Apr. 22, 2021
Upfront consideration payable	$ 20,000,000
Aggregate fair value consideration transferred	60,800,000
Milestone payments	$ 85,000,000
Percentage of payment related to collaboration or other agreements	10.00%
Payment related to collaboration or other agreements	$ 100,000,000
Consideration transferred	135,487,000
Loss on initial consolidation of VIE	11,855,000
Stock-based compensation expense associated with accelerated vesting for certain stock options		$ 4,639,000	4,639,000
Fair value of contingent milestone payments	$ 48,465,000
Adjustments to fair value of contingent milestone payments			$ 0
Number of shares that would be issued upon milestone achievement			2,351,314
Average share value of 5-day		$ 36.15	$ 36.15
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		$ 924,000	$ 924,000
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 Arrangement with Genentech - Additional Information (Detail) - USD ($)	May 13, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Collaboration And License Arrangement [Line Items]
Collaboration revenue		$ 844,000		$ 1,796,000
Contract asset		4,193,000		$ 4,193,000	$ 7,654,000
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				86,134,000
Non-refundable milestone payment for completion amount				5,000,000
Variable consideration related to reimbursements due for research and development services				1,134,000
Development based milestone payments under agreement				0
Regulatory based milestone payments under agreement				0
Collaboration revenue		786,000		1,738,000
Genentech [Member] | Genentech Agreement [Member] | Research and Development Services [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue		386,000		1,164,000
Genentech [Member] | Genentech Agreement [Member] | Transfer of Active Pharmaceutical Ingredients [Member]
Collaboration And License Arrangement [Line Items]
Collaboration revenue			$ 317,000		$ 0
Contract asset		4,193,000		4,193,000
Genentech [Member] | Genentech Agreement [Member] | Stand-alone Selling Prices (“SSP”) [Member]
Collaboration And License Arrangement [Line Items]
Collaboration agreement transaction price				86,134,000
Genentech [Member] | Genentech Agreement [Member] | Stand-alone Selling Prices (“SSP”) [Member] | Transfer of License [Member]
Collaboration And License Arrangement [Line Items]
Remaining performance obligations		82,512,000,000		82,512,000,000
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		2,891,000,000		2,891,000,000
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		$ 317,000,000		317,000,000
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)	6 Months Ended
	Jun. 30, 2021
Common Stock [Abstract]
Common Stock Restriction Period	4 years

Share-Based Payments - Addition

Share-Based Payments - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jul. 08, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Award, Number of Shares Authorized	10,653,994	8,376,080
Total unrecognized compensation cost related to the unvested stock options, Value	$ 132,744
Total unrecognized compensation cost related to the unvested stock options, Weighted average period	2 years 8 months 15 days

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 16,147	$ 4,032	$ 25,818	$ 5,487
Research and development expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	10,145	1,941	14,296	2,838
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 6,002	$ 2,091	$ 11,522	$ 2,649

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				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (193,399)	$ (42,184)	$ (26,724)	$ (24,886)	$ (235,582)	$ (51,610)
Net loss per share, basic and diluted	$ (2.10)		$ (6.06)		$ (2.58)	$ (12.06)
Weighted average shares of common stock, basic and diluted	91,939,439		4,408,470		91,188,160	4,281,169

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect	9,411,587	67,935,918	9,411,587	67,935,918
Convertible preferred stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect		59,883,877		59,883,877
Options to purchase common stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect	8,906,194	7,471,087	8,906,194	7,471,087
Restricted stock units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect	505,393	290,477	505,393	290,477
Unvested restricted stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect		290,477		290,477

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	May 26, 2021USD ($)ft²	Jun. 15, 2020USD ($)	Jun. 30, 2021USD ($)ft²Targetshares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)ft²Targetshares	Jun. 30, 2020USD ($)	May 12, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)shares
Commitments and Contingencies Disclosure [Line Items]
Accrued expenses			$ 15,405,000		$ 15,405,000			$ 5,760,000
Area of land | ft²			46,631		46,631
Right of use asset			$ 21,688,000		$ 21,688,000			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			2,096,000	$ 974,000	$ 3,941,000	$ 1,224,000
Accrued expenses			789,000		789,000			1,500,000
Prepaid balance			$ 0		$ 0			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	$ 9,875,000		$ 9,875,000		$ 7,900,000		$ 1,000,000
Research and development arrangement, expiration date		Aug. 16, 2025
Milestone payment Due			7,250,000		7,250,000
Maximum additional amount received upon milestone achievement					6,250,000
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			703,000	$ 236,000	1,105,000	$ 1,430,000
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
Contribution toward the cost of construction and tenant improvements for the premises	$ 6,221,000,000
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