0001564590-21-010276 | 10-K | XBRL Viewer

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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2020	Feb. 24, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	Revolution Medicines, Inc.
Entity Central Index Key	0001628171
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Common Stock, Shares Outstanding		73,383,206
Entity Shell Company	false
Entity Small Business	false
Entity Ex Transition Period	false
Title of 12(b) Security	Common Stock $0.0001 Par Value per Share
Trading Symbol	RVMD
Security Exchange Name	NASDAQ
Entity File Number	001-39219
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-2029180
Entity Address, Address Line One	700 Saginaw Drive
Entity Address, City or Town	Redwood City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94063
City Area Code	650
Local Phone Number	481-6801
ICFR Auditor Attestation Flag	false
Document Annual Report	true
Document Transition Report	false
Entity Public Float			$ 1,106,856,260
Documents Incorporated by Reference	Portions of the Registrant’s definitive Proxy Statement relating to the registrant’s 2021 Annual Meeting of Stockholders are incorporated herein by reference in Part III of this Annual Report on Form 10-K to the extent stated herein. The proxy statement will be filed with the Securities and Exchange Commission within 120 days of the Registrant’s fiscal year ended December 31, 2020.

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 104,268	$ 16,659
Marketable securities	336,473	106,099
Receivable from related party	6,393	8,737
Prepaid expenses and other current assets	6,988	2,486
Total current assets	454,122	133,981
Property and equipment, net	8,902	7,147
Operating lease right-of-use asset	27,435
Intangible assets, net	60,945	62,013
Goodwill	14,608	14,608
Restricted cash	1,084	214
Other noncurrent assets	305	2,566
Total assets	567,401	220,529
Current liabilities:
Accounts payable	12,609	11,400
Accrued expenses and other current liabilities	18,784	14,528
Operating lease liability	3,672
Deferred revenue, related party, current	12,111	17,124
Total current liabilities	47,176	43,052
Deferred rent, noncurrent		1,741
Deferred revenue, related party, noncurrent	8,481	14,727
Deferred tax liability	7,444	7,819
Operating lease liability	28,992
Other noncurrent liabilities	632	655
Total liabilities	92,725	67,994
Commitments and contingencies (Note 8)
Redeemable convertible preferred stock, $0.0001 par value; zero and 192,904,770 shares authorized at December 31, 2020 and 2019, respectively; zero and 39,600,423 shares issued and outstanding at December 31, 2020 and 2019, respectively; aggregate liquidation preference of zero and $308,688 at December 31, 2020 and 2019, respectively		305,109
Stockholders' equity (deficit):
Preferred stock, $0.0001 par value; 10,000,000 and zero shares authorized at December 31, 2020 and 2019, respectively; zero shares issued and outstanding at December 31, 2020 and 2019, respectively
Common stock, $0.0001 par value; 300,000,000 and 249,000,000 shares authorized at December 31, 2020 and 2019, respectively; 66,599,748 and 3,292,124 shares issued and outstanding at December 31, 2020 and 2019, respectively	7
Additional paid-in capital	740,098	4,738
Accumulated other comprehensive income	116	74
Accumulated deficit	(265,545)	(157,386)
Total stockholders' equity (deficit)	474,676	(152,574)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	$ 567,401	$ 220,529

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Temporary equity, par or stated value per share	$ 0.0001	$ 0.0001
Temporary equity, shares authorized	0	192,904,770
Temporary equity, shares issued	0	39,600,423
Temporary equity, shares outstanding	0	39,600,423
Temporary equity, liquidation preference	$ 0	$ 308,688
Preferred stock, par or stated value per share	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par or stated value per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	249,000,000
Common stock, shares, issued	66,599,748	3,292,124
Common stock, shares, outstanding	66,599,748	3,292,124

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Total revenue	$ 42,983	$ 50,041	$ 20,165
Operating expenses:
Research and development	132,252	91,755	51,084
General and administrative	21,428	12,406	9,410
Total operating expenses	153,680	104,161	60,494
Loss from operations	(110,697)	(54,120)	(40,329)
Other income (expense), net:
Interest income	2,238	2,189	777
Interest expense	(71)	(106)	(116)
Change in fair value of redeemable convertible preferred stock liability			(2,121)
Total other income (expense), net	2,167	2,083	(1,460)
Loss before income taxes	(108,530)	(52,037)	(41,789)
Benefit from income taxes	371	4,373
Net loss	(108,159)	(47,664)	(41,789)
Redeemable convertible preferred stock dividends - undeclared and cumulative	(2,219)	(14,238)	(7,031)
Net loss attributable to common stockholders	$ (110,378)	$ (61,902)	$ (48,820)
Net loss per share attributable to common stockholders - basic and diluted	$ (2.01)	$ (22.33)	$ (21.24)
Weighted-average common shares used to compute net loss per share, basic and diluted	54,874,119	2,772,589	2,298,820
Collaboration Revenue, Related Party
Revenue:
Total revenue	$ 42,983	$ 50,041	$ 19,420
Collaboration Revenue, Other
Revenue:
Total revenue			$ 745

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (108,159)	$ (47,664)	$ (41,789)
Other comprehensive income/(loss):
Unrealized gain (loss) on investments, net	42	74
Total comprehensive loss	$ (108,117)	$ (47,590)	$ (41,789)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Initial Public Offering	Follow-on Offering	Common Stock	Common Stock Initial Public Offering	Common Stock Follow-on Offering	Additional Paid-In Capital	Additional Paid-In Capital Initial Public Offering	Additional Paid-In Capital Follow-on Offering	Accumulated Other Comprehensive Income	Accumulated Deficit	Redeemable Convertible Preferred Stock	Series B Preferred Stock at $7.30 per Share	Series B Preferred Stock	Series B Preferred Stock Warp Drive	Series B Preferred Stock at $10.03 per Share	Series C Preferred Stock
Beginning balance at Dec. 31, 2017	$ (67,717)						$ 216				$ (67,933)
Redeemable convertible preferred stock, beginning balance, shares at Dec. 31, 2017												14,430,799
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2017												$ 72,248
Beginning balance, shares at Dec. 31, 2017				2,673,828
Issuance of redeemable convertible preferred stock, net of issuance costs, value													$ 58,347		$ 68,144	$ 4,332
Issuance of redeemable convertible preferred stock, net of issuance costs, shares													7,731,155		6,797,915	435,547
Convertible note payable converted into Series B redeemable convertible preferred stock														$ 2,010
Convertible note payable converted into Series B redeemable convertible preferred stock, shares														200,493
Issuance of common stock pursuant to stock option exercises	47						47
Issuance of common stock pursuant to stock option exercises, shares				107,194
Issuance of common stock pursuant to early exercised stock options, shares				546,602
Vesting of early exercised stock options and restricted stock	182						182
Repurchases of early exercised stock, shares				(118,700)
Stock-based compensation expense	855						855
Net loss	(41,789)										(41,789)
Ending balance at Dec. 31, 2018	(108,422)						1,300				(109,722)
Redeemable convertible preferred stock, ending balance, shares at Dec. 31, 2018												29,595,909
Redeemable convertible preferred stock, ending balance at Dec. 31, 2018												$ 205,081
Ending balance, shares at Dec. 31, 2018				3,208,924
Issuance of redeemable convertible preferred stock, net of issuance costs, value																	$ 100,028
Issuance of redeemable convertible preferred stock, net of issuance costs, shares																	10,004,514
Issuance of common stock pursuant to stock option exercises	114						114
Issuance of common stock pursuant to stock option exercises, shares				70,250
Issuance of common stock pursuant to early exercised stock options, shares				100,860
Vesting of early exercised stock options	163						163
Repurchases of early exercised stock, shares				(87,910)
Stock-based compensation expense	3,161						3,161
Unrealized gain (loss) on investments, net	74									$ 74
Net loss	(47,664)										(47,664)
Ending balance at Dec. 31, 2019	$ (152,574)						4,738			74	(157,386)
Redeemable convertible preferred stock, ending balance, shares at Dec. 31, 2019	39,600,423											39,600,423
Redeemable convertible preferred stock, ending balance at Dec. 31, 2019	$ 305,109											$ 305,109
Ending balance, shares at Dec. 31, 2019				3,292,124
Conversion of redeemable convertible preferred stock into common stock	305,109			$ 4			305,105					$ (305,109)
Conversion of redeemable convertible preferred stock into common stock, shares				39,600,423								(39,600,423)
Issuance of common stock upon offering, net of offering costs		$ 250,697	$ 167,767		$ 2	$ 1		$ 250,695	$ 167,766
Issuance of common stock upon offering, net of offering costs, shares					16,100,000	6,900,000
Issuance of common stock pursuant to stock option exercises	1,877						1,877
Issuance of common stock pursuant to stock option exercises, shares				694,441
Issuance of common stock related to employee stock purchase plan	832						832
Issuance of common stock related to employee stock purchase plan, shares				29,237
Issuance of common stock related to vesting of restricted stock units, shares				1,681
Vesting of early exercised stock options	199						199
Repurchases of early exercised stock, shares				(18,158)
Stock-based compensation expense	8,886						8,886
Unrealized gain (loss) on investments, net	42									42
Net loss	(108,159)										(108,159)
Ending balance at Dec. 31, 2020	$ 474,676			$ 7			$ 740,098			$ 116	$ (265,545)
Redeemable convertible preferred stock, ending balance, shares at Dec. 31, 2020	0
Ending balance, shares at Dec. 31, 2020				66,599,748

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Initial Public Offering
Stock issuance cost	$ 23,003
Follow-on Offering
Stock issuance cost	$ 11,633
Series B Preferred Stock at $7.30 per Share
Shares issued price per share			$ 7.30
Stock issuance cost			$ 204
Adjusted redeemable convertible preferred stock liability			$ 2,121
Series B Preferred Stock at $10.03 per Share
Shares issued price per share			$ 10.03
Stock issuance cost			$ 34
Series C Preferred Stock
Shares issued price per share		$ 10.03
Stock issuance cost		$ 254

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net loss	$ (108,159)	$ (47,664)	$ (41,789)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Amortization of intangible assets	1,068	1,069	198
Stock-based compensation expense	8,886	3,161	855
Depreciation and amortization	2,611	2,273	1,566
Loss on disposal of property and equipment		226	201
Loss on disposal of held for sale assets		597
Net amortization (accretion) of premium (discount) on marketable securities	968	(450)
Amortization of operating lease right-of-use asset	2,866
Change in fair value of redeemable convertible preferred stock liability			2,121
Changes in operating assets and liabilities:
Receivable from related party	2,344	(1,434)	(7,303)
Prepaid expenses and other current assets	(1,924)	(541)	(909)
Accounts payable	305	5,264	109
Accrued expenses and other current liabilities	4,855	6,042	1,906
Deferred revenue, related party	(11,259)	(13,392)	44,499
Deferred rent		(513)	(552)
Operating lease liability	(2,565)
Deferred tax liability	(375)	(4,373)
Other noncurrent assets	139	(65)
Other noncurrent liabilities	176	184	311
Net cash provided by (used in) operating activities	(100,064)	(49,616)	1,213
Cash flows from investing activities
Purchases of marketable securities	(544,133)	(172,266)
Sales of marketable securities	3,005	11,200
Maturities of marketable securities	309,828	55,490
Purchases of property and equipment	(2,933)	(2,589)	(1,499)
Proceeds from sales of property and equipment		196
Proceeds from sale of held for sale assets		6,000
Cash acquired in Warp Drive acquisition, net			160
Net cash used in investing activities	(234,233)	(101,969)	(1,339)
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	420,067
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs		100,028	60,558
Proceeds from issuance of common stock under equity incentive plans	1,877	277	420
Proceeds from issuance of common stock under employee stock purchase plan	832
Repurchases of early exercised stock options		(45)	(131)
Payments of deferred offering costs		(1,602)
Net cash provided by financing activities	422,776	98,658	60,847
Net (decrease) increase in cash, cash equivalents and restricted cash	88,479	(52,927)	60,721
Cash, cash equivalents and restricted cash - beginning of year	16,873	69,800	9,079
Cash, cash equivalents and restricted cash - end of year	105,352	16,873	69,800
Reconciliation of cash, cash equivalents and restricted cash to consolidated balance sheets
Cash and cash equivalents	104,268	16,659	69,586
Restricted cash	1,084	214	214
Cash, cash equivalents and restricted cash - end of year	105,352	16,873	69,800
Supplemental disclosure of non-cash investing and financing activities
Vesting of early exercised options and restricted stock	199	163	182
Purchases of property and equipment in accounts payable and accrued expenses and other current liabilities	1,813	380	233
Right-of-use assets obtained in exchange for operating lease liabilities	$ 21,188
Extinguishment of redeemable convertible preferred stock liability			2,314
Unpaid deferred offering costs		$ 519
Warp Drive
Supplemental disclosure of non-cash investing and financing activities
Redeemable convertible preferred stock issued in Warp Drive acquisition			68,144
Unpaid consideration for Warp Drive acquisition included within accrued expenses and other current liabilities			102
Series B Redeemable Convertible Preferred Stock
Supplemental disclosure of non-cash investing and financing activities
Conversion of convertible note payable into Series B redeemable convertible preferred stock			$ 2,010

Organization

12 Months Ended

Dec. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization

1.	Organization

Revolution Medicines, Inc. (the Company) is a clinical-stage precision oncology company focused on developing targeted therapies to inhibit frontier targets in RAS-addicted cancers. The Company was founded in October 2014 and is headquartered in Redwood City, California.

Liquidity

The Company has incurred net operating losses in each year since inception. As of December 31, 2020, the Company had an accumulated deficit of $265.5 million. Management believes that its existing cash, cash equivalents and marketable securities will enable the Company to fund its planned operations for at least 12 months following the issuance date of these consolidated financial statements. The Company has been able to fund its operations through the issuance and sale of common stock and redeemable convertible preferred stock in addition to upfront payments and research and development cost reimbursement received under the Company’s collaboration agreement with Genzyme Corporation, an affiliate of Sanofi. Future capital requirements will depend on many factors, including the timing and extent of spending on research and development and payments the Company may receive under the Sanofi collaboration agreement or future collaboration agreements, if any. There can be no assurance that, in the event the Company requires additional financing, such financing will be available at terms acceptable to the Company, if at all. Failure to generate sufficient cash flows from operations, raise additional capital and reduce discretionary spending should additional capital not become available could have a material adverse effect on the Company’s ability to achieve its business objectives.

Public offerings

On February 2020, the Company closed its initial public offering (IPO), and issued 16,100,000 shares of its common stock (including the exercise in full by the underwriters of their option to purchase an additional 2,100,000 shares of common stock) at a price to the public of $17.00 per share for net proceeds of $250.7 million, after deducting underwriting discounts and commissions of $19.2 million and expenses of $3.8 million.

In July 2020, the Company issued and sold 6,900,000 shares of its common stock in an underwritten public offering (including the exercise in full by the underwriters of their option to purchase an additional 900,000 shares of the Company’s common stock) at a price of $26.00 per share for net proceeds of $167.8 million, after deducting underwriting discounts and commissions of $10.8 million and expenses of $0.8 million.

In February 2021, the Company issued and sold 6,666,666 shares of its common stock in an underwritten public offering at a price of $45.00 per share (including the exercise in full by the underwriters of their option to purchase an additional 869,565 shares of its common stock) for net proceeds of approximately $281.3 million, after deducting underwriting discounts and commissions.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of significant accounting policies

Basis of presentation

The consolidated financial statements have been prepared in conformity with generally accepted accounting principles in the United States (GAAP) and applicable rules of the Securities and Exchange Commission (SEC) regarding financial reporting and, in the opinion of management, include all normal and recurring adjustments which are necessary to state fairly the Company's financial position and results of operations for the reported periods. The consolidated financial statements for the years ended December 31, 2020, 2019 and 2018 include the accounts of the Company and its wholly owned subsidiary, Warp Drive Bio, Inc. (Warp Drive). All intercompany balances and transactions have been eliminated in consolidation. The functional and reporting currency of the Company and its subsidiary is the U.S. dollar.

Reverse stock split

On February 7, 2020, the Company amended and restated its amended and restated certificate of incorporation to effect a 1-for-4.8661 reverse stock split of the Company’s common stock and redeemable convertible preferred stock. The par value and authorized shares of the common stock and redeemable convertible preferred stock were not adjusted as a result of the reverse stock split. All issued and outstanding common stock, options to purchase common stock and per share amounts contained in the financial statements have been retroactively adjusted to give effect to the reverse stock split for all periods presented.

Use of estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, clinical accruals, valuation of in-process research and development and developed technologies, income taxes, useful lives of property and equipment and intangible assets, impairment of goodwill, and stock-based compensation. The extent to which the COVID-19 pandemic may directly or indirectly impact the Company’s business, financial condition and results of operations is highly uncertain and subject to change. The Company considered the potential impact of the COVID-19 pandemic on its estimates and assumptions and there was not a material impact to the Company’s consolidated financial statements as of and for the twelve months ended December 31, 2020. Actual results could materially differ from the Company’s estimates, and there may be changes to the estimates in future periods.

Cash and cash equivalents

The Company considers all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents. As of December 31, 2020 and 2019, cash equivalents consist of amounts invested in money market funds and investments in U.S. government agency bonds, commercial paper and corporate bonds with original maturities of three months or less at the date of purchase.

Marketable securities

Investments in marketable securities primarily consist of U.S. government debt securities, U.S. government agency bonds, commercial paper and corporate bonds. The Company has classified its marketable securities as available-for-sale and may sell these securities prior to their stated maturities. The Company views these marketable securities as available to support current operations and classifies marketable securities with maturities beyond 12 months as current assets. The Company’s investments in marketable securities are carried at estimated fair value, which is derived from independent pricing sources based on quoted prices in active markets for similar securities. Unrealized gains and losses are reported as a component of accumulated other comprehensive loss. The amortized cost of marketable securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income on the consolidated statements of operations. Realized gains and losses are included in interest income on the consolidated statements of operations.

The Company periodically evaluates its investments to assess whether those with unrealized loss positions are other than temporarily impaired. The Company considers various factors in determining whether to recognize an impairment charge. If the Company determines that the decline in an investment’s fair value is other-than-temporary, the difference is recognized as an impairment loss in the consolidated statements of operations. As of December 31, 2020, no other-than-temporary-impairment has been recorded.

Restricted cash

As of December 31, 2020 and 2019, the Company had $1.1 million and $0.2 million, respectively, of noncurrent restricted cash related to Company issued letters of credit in connection with leases. These amounts are held in separate bank accounts to support letter of credit agreements for the leases.

Concentration of credit risk and other risks and uncertainties

Financial instruments that potentially subject the Company to concentration of credit risk consist of cash, cash equivalents and marketable securities. The Company’s cash is held by two financial institution in the United States, which management believes to be of high credit quality. The Company invests in money market funds, U.S. government debt securities, U.S. government agency bonds, commercial paper and corporate bonds. The Company has not experienced any losses on its deposits of cash and cash equivalents.

The Company is subject to credit risk as its receivable and collaboration revenue, related party are entirely related to its collaboration agreement with Sanofi. See Note 9, “Sanofi collaboration agreement.”

The Company’s clinical trial sites for its RMC-4630 clinical studies may be affected by the COVID-19 outbreak due to prioritization of hospital resources toward the COVID-19 outbreak, travel or quarantine restrictions imposed by governments, and the inability to access sites for initiation and patient monitoring and enrollment. As a result, patient screening, new patient enrollment, monitoring and data collection may be affected or delayed. The Company is aware that several clinical sites involved in its RMC-4630 clinical studies temporarily stopped or delayed enrolling new patients, with exemptions if appropriate, and it is possible that these or other clinical sites may be similarly affected in the future. These developments may delay the Company’s clinical trial timelines. Some of the Company’s third-party manufacturers which it uses for the supply of materials for product candidates or other materials necessary to manufacture product to conduct preclinical tests and clinical trials and contract research organizations may be impacted by COVID-19, and should they experience disruptions, such as temporary closures or suspension of services, the Company would likely experience delays in advancing clinical trials.

Fair value measurement

The carrying amounts of the Company’s certain financial instruments, including cash equivalents, accounts payable and accrued expenses and other current liabilities approximate fair value due to their relatively short maturities and market interest rates, if applicable.

Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows:

Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 2—Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active; and

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Property and equipment, net

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed on a straight-line basis over the estimated useful lives of the related assets, which is generally three to five years. Leasehold improvements are amortized using the straight-line method over the shorter of the assets’ estimated useful lives or the remaining term of the lease. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in the consolidated statement of operations.

Useful lives of property and equipment are as follows:

Property and equipment		Estimated useful life
Laboratory equipment		4-5 years
Leasehold improvements		Lesser of estimated useful life or remaining lease term
Computer equipment and software		3 years
Furniture and fixtures		5 years

Leases

The Company determines if an arrangement is, or contains, a lease at inception and then classifies the lease as operating or financing based on the underlying terms and conditions of the contract. Leases with terms greater than one year are initially recognized on the balance sheet as right-of-use assets and lease liabilities based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes the incremental borrowing rate, which is the rate incurred to borrow, on a collateralized basis, an amount equal to the lease payments over a similar term and in a similar economic environment of the applicable country or region. Variable lease payments are excluded from the right-of-use assets and operating lease liabilities and are recognized in the period in which the obligation for those payments is incurred.

Impairment of long-lived assets

Long-lived assets are reviewed for indications of possible impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. Recoverability is measured by comparison of the carrying amounts of the asset group to the future undiscounted cash flows attributable to these assets. An impairment loss is recognized to the extent an asset group is not recoverable, and the carrying amount exceeds the projected discounted future cash flows arising from these assets. There were no impairments of long-lived assets for any of the periods presented.

Acquired intangible assets

Indefinite-lived intangible assets represent the estimated fair value assigned to in-process research and development (IPR&D) acquired in a business combination. The Company reviews indefinite-lived intangible assets for impairment at least annually or more frequently if events or changes in circumstances indicate that the carrying value of the assets might not be recoverable. If the carrying value of an indefinite-lived intangible asset exceeds its fair value, then it is written down to its adjusted fair value. As of December 31, 2020, there have been no such impairments. For IPR&D, if a product candidate derived from the indefinite-lived intangible asset is developed and commercialized, the useful life will be determined, and the carrying value will be amortized prospectively over that estimated useful life. Alternatively, if a product candidate is abandoned, the carrying value of the intangible asset will be charged to research and development expenses in the consolidated statements of operations.

Finite-lived intangible assets acquired in a business combination are recognized separately from goodwill and are initially recognized at their fair value at the acquisition date and are carried at cost less accumulated amortization and impairment. Amortization is computed using the straight-line method over the estimated useful lives of the respective finite-lived intangible assets. Intangible assets are reviewed for impairment at least annually or more frequently if indicators of potential impairment exist. As of December 31, 2020, no such impairment has been recorded.

Goodwill

Goodwill represents the excess of the purchase price over the estimated fair value of the net tangible and intangible assets acquired in a business combination. The Company reviews goodwill for impairment at least annually or more frequently if events or changes in circumstances indicate that the carrying value of goodwill may not be recoverable. Goodwill is tested for impairment at the reporting unit level by first assessing the qualitative factors to determine whether it is more likely than not that the fair value of the Company’s single reporting unit is less than its carrying amount. Qualitative indicators assessed include consideration of macroeconomic, industry and market conditions, the Company’s overall financial performance and personnel or strategy changes. Based on the qualitative assessment, if it is determined that it is more likely than not that its fair value is less than its carrying amount, the fair value of the Company’s single reporting unit is compared to its carrying value. Any excess of the goodwill carrying amount over the fair value is recognized as an impairment loss, and the carrying value of goodwill is written down to fair value. As of December 31, 2020, no goodwill impairment has been identified.

Redeemable convertible preferred stock

The Company records all shares of redeemable convertible preferred stock at their respective fair values on the dates of issuance, net of issuance costs. The redeemable convertible preferred stock is recorded outside of permanent equity because while it is not mandatorily redeemable, in the event of certain events considered not solely within the Company’s control, such as a merger, acquisition or sale of all or substantially all of the Company’s assets (each, a “deemed liquidation event”), the redeemable convertible preferred stock will become redeemable at the option of the holders of at least a majority of the then outstanding such shares. The Company has not adjusted the carrying values of the redeemable convertible preferred stock to the liquidation preferences of such shares because it is uncertain whether or when a deemed liquidation event would occur that would obligate the Company to pay the liquidation preferences to holders of shares of redeemable convertible preferred stock. Subsequent adjustments to the carrying values to the liquidation preferences will be made only when it becomes probable that such a deemed liquidation event will occur.

Redeemable convertible preferred stock liability

The Company’s March 2018 issuance and sale of Series B redeemable convertible preferred stock was tranched into two funding dates, a first closing in March 2018, and a second closing to purchase additional shares in June 2018. The Company classified the obligation for the future purchase of additional shares under the second closing as a liability on the Company’s consolidated balance sheets as the obligation met the definition of a freestanding financial instrument. This redeemable convertible preferred stock tranche liability was initially recorded at a fair value of $0.2 million upon the date of issuance and was subsequently remeasured to fair value at each reporting date using Level 3 fair value inputs. Changes in the fair value of the redeemable convertible preferred stock tranche obligation of $2.1 million were recognized as a component of other income (expense), net in the consolidated statements of operations and until the tranche obligation was fulfilled and extinguished upon the second closing in June 2018.

Revenue recognition

The Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

The Company enters into collaboration agreements under which it may obtain upfront license fees, research and development funding, and development, regulatory and commercial milestone payments and royalty payments. The Company’s performance obligations under these arrangements may include licenses of intellectual property, sales and distribution rights, research and development services, delivery of manufactured product and/or participation on joint steering committees.

Licenses of intellectual property: If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from upfront license fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring proportional performance for purposes of recognizing revenue from non-refundable, upfront fees. The Company evaluates the measure of proportional performance each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Research, development and regulatory milestone payments: At the inception of each arrangement that includes research, development, or regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price. The Company uses the most likely amount method for research, development and regulatory milestone payments. Under the most likely amount method, an entity considers the single most likely amount in a range of possible consideration amounts. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price.

Sales-based milestones and royalties: For arrangements that include sales-based milestone or royalty payments based on the level of sales, and in which the license is deemed to be the predominant item to which the sales-based milestone or royalties relate to, the Company recognizes revenue in the period in which the sales-based milestone is achieved and in the period in which the sales associated with the royalty occur. To date, the Company has not recognized any or sales-based milestone or royalty revenue resulting from its collaboration arrangements.

Deferred revenue represents amounts received by the Company for which the related revenues have not been recognized because one or more of the revenue recognition criteria have not been met. The current portion of deferred revenue represents the amount to be recognized within one year from the balance sheet date based on the estimated performance period of the underlying performance obligation. The noncurrent portion of deferred revenue represents amounts to be recognized after one year through the end of the performance period of the performance obligation.

Research and development expenditures

Research and development expenses consist of costs incurred for the Company’s own and for collaborative research and development activities. Research and development costs are expensed as incurred. Research and development costs consist of salaries and benefits, including associated stock-based compensation, and laboratory supplies and facility costs, as well as fees paid to other entities that conduct certain research and development activities on the Company’s behalf. The Company estimates preclinical study and clinical trial expenses based on the services performed pursuant to contracts with research institutions and contract research organizations and clinical manufacturing organizations that conduct and manage preclinical studies and clinical trials on the Company’s behalf based on actual time and expenses incurred by them. Further, the Company accrues expenses related to clinical trials based on the level of patient activity according to the related agreement. The Company monitors patient enrollment levels and related activity to the extent reasonably possible and adjusts estimates accordingly.

Stock-based compensation

The Company measures its stock-based awards granted to employees and directors based on the estimated fair values of the awards and recognizes the compensation on a straight-line basis over the requisite service period. The fair value of options issued under the employee stock purchase plan is calculated using the Black-Scholes option-pricing model. Restricted stock units are valued based on the closing price of the Company’s common stock on the date of grant.

Comprehensive loss

For the years ended December 31, 2020 and 2019, other comprehensive loss includes net unrealized gains on marketable securities. For the year ended December 30, 2018, there were no components of other comprehensive loss for the Company, and comprehensive loss is the same as the net loss.

Income taxes

Income taxes are accounted for under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Management makes an assessment of the likelihood that the resulting deferred tax assets will be realized. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. Due to the Company’s historical operating performance and the recorded cumulative net losses in prior fiscal periods, the net deferred tax assets have been fully offset by a valuation allowance.

The Company recognizes uncertain income tax positions at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Changes in recognition or measurement are reflected in the period in which judgment occurs. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of interest expense.

Net loss per share attributable to common stockholders

Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, stock options, common stock subject to repurchase related to unvested restricted stock awards and early exercise of stock options are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities as the redeemable convertible preferred stock is considered a participating security because it participates in dividends with common stock. The Company also considers the shares issued upon the early exercise of stock options subject to repurchase to be participating securities because holders of such shares have non-forfeitable dividend rights in the event a dividend is paid on common stock. The holders of all series of redeemable convertible preferred stock and the holders of early exercised shares subject to repurchase do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per share is the same as basic net loss per share for those periods.

Deferred offering costs

The Company capitalizes certain legal, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ deficit (equity) as a reduction of additional paid-in capital generated as a result of the equity financing. Should an in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations. As of December 31, 2020 and 2019, zero and $2.1 million of deferred offering costs, respectively, were capitalized in other noncurrent assets on the consolidated balance sheets.

Segment reporting

The Company has one operating and reportable segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purposes of allocating resources and evaluating financial performance. All of the Company’s long-lived assets are located in the United States.

Retirement plans

The Company maintains a 401(k) retirement plan for its employees. The Company is responsible for administrative costs of the 401(k) plan. The Company may, at its discretion, make matching or profit-sharing contributions to the 401(k) plan. For the years ended December 31, 2020, 2019 and 2018, the Company made $0.2 million, $0.2 million and zero matching contributions, respectively, under the plan.

Recent accounting pronouncements

From time to time, new accounting pronouncements are issued by the FASB, under its ASC or other standard setting bodies, and adopted by the Company as of the specified effective date, unless otherwise discussed below.

Recently adopted accounting pronouncements

In February 2016, the FASB issued ASU No. 2016-02, Leases (ASU 2016-02). ASU 2016-02 provides accounting guidance for both lessee and lessor accounting models. In July 2018, the FASB issued supplemental adoption guidance and clarification to ASC 842 within ASU 2018-10, Codification Improvements to Topic 842, Leases, ASU 2018-11, Leases (Topic 842): Targeted Improvements and ASU 2019-01, Leases (Topic 842): Codification Improvements. ASU 2018-11 provides another transition method in addition to the existing modified retrospective transition method by allowing entities to initially apply the new leasing standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption.

The Company adopted these ASUs on January 1, 2020. For its operating leases with a term greater than twelve months, the Company recognizes a right-of-use asset and a lease liability on its consolidated balance sheets. The Company adopted the new standard using the modified retrospective approach, which resulted in the initial recognition of a lease liability of $11.5 million, and a right‑to‑use asset of $9.1 million, with no adjustment to the accumulated deficit balance. In connection with the lease adoption, the Company also derecognized deferred rent of $2.4 million. The adoption of the new standard did not have an impact on the consolidated statements of operations. The lease liability is determined as the present value of future lease payments using an estimated rate of interest that the Company would pay to borrow equivalent funds on a collateralized basis at the lease commencement date. In order to estimate the incremental borrowing rate, management estimated its credit rating, adjusted the credit rating for the nature of the collateral, and benchmarked the borrowing rate against observable yields on comparable securities with a similar term. As of the adoption date, the Company estimated the incremental borrowing rate to be approximately 5%. The Company determined the lease term at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. The Company elected the practical expedients permitted under ASU 2018-11, which among other things, allowed the Company to carry forward the historical lease classification of those leases in place as of January 1, 2020. The Company elected to exclude from its consolidated balance sheets recognition of leases having a term of 12 months or less (short-term leases). The Company elected to apply the practical expedient and accounted for each lease component and related non-lease component as one single component.

In June 2018, the FASB issued ASU No. 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting (ASU 2018-07). ASU 2018-07 simplifies the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payments to employees, with certain exceptions. The Company adopted ASU 2018-07 on January 1, 2020 and concluded that adoption of the standard did not have a material impact on its consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement Disclosure Framework (ASU 2018-13). ASU 2018-13 is part of a broader disclosure framework project by the FASB to improve the effectiveness of disclosures by more clearly communicating the information to the user. ASU 2018-13 is applicable to the Company for the fiscal year beginning after December 15, 2019. The Company adopted the standard on January 1, 2020 and concluded that adoption of the standard did not have a material impact on its consolidated financial statements.

In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606 (ASU 2018-18). ASU 2018-18 clarifies that certain transactions between collaborative arrangement participants should be accounted for as revenue under Topic 606 when the counterparty is a customer for a distinct good or service (i.e. a unit of account). For units of account that are in the scope of Topic 606, all of the guidance in Topic 606 should be applied, including the guidance on recognition, measurement, presentation and disclosure. ASU 2018-18 also adds a reference in ASC Topic 808, Collaborative Arrangements (Topic 808) to the unit of account guidance in Topic 606 and requires that it be applied only to assess whether transactions in a collaborative arrangement are in the scope of Topic 606. ASU 2018-18 preclude entities from presenting amounts related to transactions with a counterparty in a collaborative arrangement that is not a customer as revenue from contracts with customers. The Company adopted the standard on January 1, 2020 and concluded that adoption of the standard did not have a material impact on its consolidated financial statements.

Recent 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 (ASU 2016-13), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in earlier recognition of credit losses. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses (ASU 2018-19) which narrowed the scope and changed the effective date for non-public entities for ASU 2016-13. The FASB subsequently issued supplemental guidance within ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief (ASU 2019-05). ASU 2019-05 provides an option to irrevocably elect the fair value option for certain financial assets previously measured at amortized cost basis. ASU 2016-13 is applicable to the Company for the fiscal year beginning after December 15, 2021. Early adoption is permitted. The Company is currently evaluating the impact the adoption of these ASUs will have on its consolidated financial statements and related disclosures.

In August 2018, the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a cloud computing arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use-software. This ASU is effective for the Company for the fiscal year beginning after December 15, 2020, and interim periods within fiscal years beginning after December 31, 2021. The Company is currently evaluating the impact of this ASU on the Company’s consolidated financial statements.

In December 2019, the Financial Accounting Standards Board (FASB) issued ASU 2019-12, Income Taxes (Topic 740)-Simplifying the Accounting for Income Taxes (ASU 2019-12). ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and clarifying and amending existing guidance. This ASU is effective for the Company for the fiscal year beginning after December 15, 2021 and interim periods within fiscal years beginning after December 15, 2021. ASU 2019-12 will be effective for the Company in the first quarter of 2021 with early adoption permitted. The Company is currently assessing the impact of ASU 2019-12 on its consolidated financial statements.

In October 2020, the FASB issued ASU 2020-08, Codification Improvements to Subtopic 310-20, Receivables-Nonrefundable Fees and Other Costs (ASU 2020-08). This ASU clarifies that an entity should reevaluate whether a callable debt security is within the scope of ASC paragraph 310-20-35-33 for each reporting period. The guidance is effective for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. Early application is not permitted. All entities should apply ASU 2020-08 on a prospective basis as of the beginning of the period of adoption for existing or newly purchased callable debt securities. The Company is currently evaluating the impact of ASU 2020-08 on the Company’s consolidated financial statements.

In October 2020, FASB issued ASU2020-10, Codification Improvements. This update contains amendments that improve the consistency of the Codification by including all disclosure guidance in the appropriate Disclosure Section (Section 50). Many of the amendments arose because the Board provided an option to give certain information either on the face of the financial statements or in the notes to financial statements and that option only was included in the Other Presentation Matters Section (Section 45) of the Codification. The option to disclose information in the notes to financial statements should have been codified in the Disclosure Section as well as the Other Presentation Matters Section (or other Section of the Codification in which the option to disclose in the notes to financial statements appears). The amendments in this Update do not change GAAP and, therefore, are not expected to result in a significant change in practice. The amendments are effective for the Company for fiscal years beginning after December 15, 2021, including interim period within those fiscal years. Early adoption is permitted. Adoption shall be applied retrospectively. The Company is currently evaluating the impacts of the provisions of ASU 2020-10 on its consolidated financial statements and related disclosures.

Fair Value Measurements

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

3.	Fair value measurements

The following table presents information about the Company’s financial assets that are measured at fair value and indicates the fair value hierarchy of the valuation:

	December 31, 2020
	Total		Level 1		Level 2		Level 3
	(in thousands)
Assets:
Money market funds ⁽¹⁾	$	16,696	$	16,696	$	—	$	—
Commercial paper ^{(1, 2)}		151,663		—		151,663		—
U.S. government and agency securities^{(1, 2)}		270,520		—		270,520		—
Corporate bonds ^{(1, 2)}		3,200		—		3,200		—
Total	$	442,079	$	16,696	$	425,383	$	—

	December 31, 2019
	Total		Level 1		Level 2		Level 3
	(in thousands)
Assets:
Money market funds ⁽¹⁾	$	9,369	$	9,369	$	—	$	—
Commercial paper ⁽²⁾		32,597		—		32,597		—
U.S. government and agency securities⁽²⁾		42,814		—		42,814		—
Corporate bonds ⁽²⁾		38,837		—		38,837		—
Total	$	123,617	$	9,369	$	114,248	$	—

(1)Included in cash and cash equivalents on the consolidated balance sheets.

(2)Included in marketable securities on the consolidated balance sheets.

Money market funds are measured at fair value on a recurring basis using quoted prices. U.S. government debt securities, U.S. government agency bonds, commercial paper and corporate bonds are measured at fair value, which is derived from independent pricing sources based on quoted prices in active markets for similar securities.

There were no transfers between Levels 1, 2 or 3 for any of the periods presented.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Available-for-sale Securities

12 Months Ended

Dec. 31, 2020

Investments Debt And Equity Securities [Abstract]

Available-for-sale securities

4.	Available-for-sale securities

The following tables summarize the estimated value of the Company’s available-for-sale marketable securities and cash equivalents and the gross unrealized gains and losses:

	December 31, 2020
			Gross		Gross
	Amortized		unrealized		unrealized			Estimated
	cost		gain		loss			fair value
	(in thousands)
Marketable securities:
Commercial paper	$	69,871	$	—	$	(5	)	$	69,866
U.S. government and agency securities		266,481		131		(5	)		266,607
Total marketable securities		336,352		131		(10	)		336,473
Cash equivalents:
Money market funds		16,696		—		—			16,696
Commercial paper		81,800		—		(3	)		81,797
U.S. government and agency securities		3,913		—		—			3,913
Corporate bonds		3,202		—		(2	)		3,200
Total cash equivalents		105,611		—		(5	)		105,606
Total available-for-sale investments	$	441,963	$	131	$	(15	)	$	442,079

	December 31, 2019
			Gross		Gross
	Amortized		unrealized		unrealized			Estimated
	cost		gain		loss			fair value
	(in thousands)
Marketable securities:
Commercial paper	$	24,446	$	3	$	(1	)	$	24,448
U.S. government and agency securities		42,777		39		(2	)		42,814
Corporate bonds		38,802		37		(2	)		38,837
Total marketable securities		106,025		79		(5	)		106,099
Cash equivalents:
Money market funds		9,369		—		—			9,369
Commercial paper		8,149		—		—			8,149
Total cash equivalents		17,518		—		—			17,518
Total available-for-sale investments	$	123,543	$	79	$	(5	)	$	123,617

The amortized cost and estimated fair value of the Company’s available-for-sale marketable securities and cash equivalents by contractual maturity are summarized below as of December 31, 2020:

	December 31, 2020
			Gross		Gross
	Amortized		unrealized		unrealized			Estimated
	cost		gain		loss			fair value
	(in thousands)
Mature in one year or less	$	409,968	$	127	$	(15	)	$	410,080
Mature after one year through two years		31,995		4		—			31,999
Total marketable securities	$	441,963	$	131	$	(15	)	$	442,079

Balance Sheet Components

12 Months Ended

Dec. 31, 2020

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

5.	Balance sheet components

Property and equipment, net

Property and equipment, net consists of the following:

	December 31,
	2020			2019
	(in thousands)
Laboratory equipment	$	9,978		$	8,032
Leasehold improvements		3,387			3,342
Computer equipment and software		1,578			1,284
Furniture and fixtures		48			48
Construction in progress		1,981			—
		16,972			12,706
Less: accumulated depreciation and amortization		(8,070	)		(5,559	)
Property and equipment, net	$	8,902		$	7,147

Depreciation and amortization expense for property and equipment amounted to $2.6 million, $2.3 million and $1.6 million for the years ended December 31, 2020, 2019 and 2018, respectively.

Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consist of the following:

	December 31,
	2020		2019
	(in thousands)
Accrued compensation	$	7,736	$	4,069
Accrued research and development		10,459		7,195
Deferred rent, current		—		609
Accrued professional services		492		1,607
Other		97		1,048
Total accrued expenses and other current liabilities	$	18,784	$	14,528

Acquisition of Warp Drive

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Acquisition of Warp Drive

6.	Acquisition of Warp Drive

In October 2018, the Company acquired all outstanding shares of Warp Drive in exchange for issuing 6,797,915 shares of the Company’s Series B redeemable convertible preferred stock and $0.9 million in other consideration, for total consideration of $69.0 million. Warp Drive was a privately held biotechnology company based in Cambridge, Massachusetts.

Warp Drive’s RAS programs include compounds targeting various cancer indications, while its tri-complex platform is targeted at identifying presenter proteins for binding with small molecules and a target. Additionally, Warp Drive had a genome mining platform that is subject to a collaboration agreement with Hoffman-La Roche Ltd. (Roche) involving research in the area of neomorph antibiotics.

Pursuant to ASC Topic 805, Business Combinations, the transaction was determined to be a business combination and was accounted for using the acquisition method of accounting. The following table presents a summary of the purchase price consideration for the acquisition:

	(in thousands)
Series B redeemable convertible preferred stock	$	68,144
Cash		1,172
Contingently returnable consideration asset		(310	)
Total consideration	$	69,006

The fair value of $10.03 per share of Series B redeemable convertible preferred stock was determined using a discounted cash flow model to estimate the value of the Company’s equity, and subsequently allocated to the Series B redeemable convertible preferred stock using an option pricing method.

The shares and cash issued as part of the transaction include 494,771 shares and less than $0.1 million of cash subject to a holdback based on certain events associated with Warp Drive’s agreement with Roche. The shares and cash subject to the holdback were issued on closing of the acquisition, but would be required to be returned to the Company if the holdback events did not occur. On the acquisition date, the Company determined the fair value of the holdback provision was $0.3 million and recorded it as a contingently returnable consideration asset on its consolidated balance sheet. The shares subject to the holdback retained their voting rights. In March 2019, the events subject to the holdback occurred and the issued shares and cash were no longer subject to the holdback provision. See Note 3, “Fair value measurements,” for a description of the determination of the fair value of the contingently returnable consideration asset.

During the year ended December 31, 2018, the Company incurred $0.4 million of acquisition-related costs as a result of the Warp Drive acquisition, which were recorded as general and administrative expenses in the consolidated statements of operations. The Company also paid $0.6 million in transaction costs incurred by Warp Drive related to Warp Drive’s advisors, which was included as part of the purchase price consideration.

The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date:

	(in thousands)
Assets acquired:
Cash and other current assets	$	1,594
Property and equipment		2,151
In-process research and development - RAS programs		55,800
Developed technology - tri-complex platform		7,480
Developed technology - genome mining platform		6,100
Total assets acquired		73,125
Liabilities assumed:
Accounts payable and other accrued liabilities		3,790
Convertible note payable, related party		2,000
Deferred revenue		745
Deferred tax liability		12,192
Total liabilities assumed		18,727
Goodwill		14,608
Total	$	69,006

The valuations of the IPR&D—RAS programs and developed technology—genome mining platform were determined using the income approach, which discounts expected future cash flows to present value. The discount rates used were between 13% and 14%. The projected cash flows were based on key assumptions such as: estimates of revenues and operating profits related to each program or platform considering its stage of development on the acquisition date; the time and resources needed to complete the development and approval of product candidates; the life of the potential commercialized products and associated risks, including the inherent difficulties and uncertainties in developing a product candidate such as obtaining marketing approval from the FDA and other regulatory agencies; and risks related to the viability of and potential alternative treatments in any future target markets.

Intangible assets associated with acquired IPR&D relate to the RAS programs. Management determined that the estimated acquisition-date fair value of the intangible asset related to IPR&D was $55.8 million, which was comprised of $44.1 million related to the KRAS^G12C program and $11.7 million related to the KRAS^G12D program. The KRAS^G12C and the KRAS^G12D programs are each focused on developing inhibitors which target specific mutations of KRAS(ON) proteins. The acquired IPR&D is considered to be an indefinite-lived asset until the completion or abandonment of the research and development efforts. The acquired IPR&D will not be amortized until completion of the related products, which is determined by when the underlying programs reach technological feasibility and commence commercial production. Upon completion, the acquired IPR&D will be amortized over its useful life.

The valuation of the developed technology—tri-complex platform was based on a replacement cost approach as the Company’s management intends to leverage the platform internally, but does not have the ability to assign a specific income stream to the asset. The tri-complex platform was accounted for as developed technology and is being amortized over 7 years. Amortization expense for the years ended December 31, 2020, 2019 and 2018 was $1.1 million, $1.1 million and $0.2 million, respectively.

The genome mining platform, including the associated Roche collaboration agreement, was accounted for as held for sale developed technology and was divested in January 2019 to Gingko Bioworks (Gingko). The Company received $6.0 million in cash consideration from Gingko and Roche as part of the transaction, and is entitled to receive up to 25% of future milestones earned by Gingko under the collaboration agreement with Roche included as part of this sale. The Company recognized a loss on disposal of $0.6 million during the year ended December 31, 2019, which was recorded in research and development expenses in the consolidated statements of operations.

The Company assumed a convertible promissory note (the Convertible Note), as part of the Company’s acquisition of Warp Drive. See Note 15, “Related party relationships.”

Deferred revenue consists of the remaining estimated cost obligations, including mark-up, associated with the collaboration with Roche. The entire amount was recognized as revenue during the year ended December 31, 2018 and included under collaboration revenue, other in the consolidated statements of operations.

The Company recorded $14.6 million in goodwill associated with this acquisition, which relates to the establishment of a deferred tax liability for the non-deductible in-process research and development intangible assets acquired and synergies resulting from the acquisition. Goodwill will not be amortized but will be tested at least annually for impairment.

Subsequent to the acquisition, the Company recorded $1.4 million of severance costs during the year ended December 31, 2018 in the consolidated statement of operations.

The acquisition is considered a material business combination and accordingly unaudited pro forma information presented below for the year ended December 31, 2018, includes the effects of pro forma adjustments as if the acquisition of Warp Drive occurred on January 1, 2017, the beginning of the comparable prior annual reporting period. The unaudited pro forma results include adjustments related to the following: (i) amortization expense related to the fair value of identifiable intangible assets acquired, (ii) impact of the genome mining deposition, (iii) alignment of Warp Drive’s revenue recognition policy to the Company’s adoption method and adoption date of ASC 606, (iv) inclusion of incurred acquisition-related and severance costs as of the earliest period presented, (v) elimination of interest expense and gain related to Warp Drive’s convertible note payable, which was converted into Warp Drive common stock immediately prior to the acquisition and subsequently converted into the Company’s Series B redeemable convertible preferred stock in connection with the acquisition, and (vi) adjustment of depreciation expense related to the estimated useful lives of property and equipment acquired.

The pro forma financial information presented below is not necessarily indicative of the results of operations that would have been achieved if the acquisition occurred at the beginning of the earliest period presented, nor is it intended to be a projection of future results.

	Year Ended December 31,
	2018
	(unaudited, in thousands)
Revenue	$	20,302
Net loss		(57,151	)

Revenues associated with Warp Drive included in the Company’s consolidated statement of operations were $0.7 million for the period from acquisition date to December 31, 2018. Net loss associated with Warp Drive included in the Company’s consolidated statement of operations was $4.2 million for the period from the acquisition date to December 31, 2018.

Intangible Assets and Goodwill

12 Months Ended

Dec. 31, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible Assets and Goodwill

7.	Intangible assets and goodwill

Intangible assets, net

Intangible assets, net consist of the following as of December 31, 2020:

	Gross value		Accumulated amortization			Net book value		Weighted- average remaining useful life
	(in thousands)							(in years)
In-process research and development - RAS Programs	$	55,800	$	—		$	55,800	n/a
Developed technology - tri-complex platform		7,480		(2,335	)		5,145		4.8
Total	$	63,280	$	(2,335	)	$	60,945

Amortization expense for the years ended December 31, 2020, 2019 and 2018 were $1.1 million, $1.1 million and $0.2 million, respectively. See Note 6, “Acquisition of Warp Drive”, for a description of the assets acquired as part of the Warp Drive acquisition.

As of December 31, 2020, future amortization expense is as follows:

	Amount
	(in thousands)
2021		1,069
2022		1,069
2023		1,069
2024		1,069
2025		869
Total	$	5,145

Intangible assets, net consist of the following as of December 31, 2019:

	Gross value		Accumulated amortization			Net book value		Weighted- average remaining useful life
	(in thousands)							(in years)
In-process research and development - RAS Programs	$	55,800	$	—		$	55,800	n/a
Developed technology - tri-complex platform		7,480		(1,267	)		6,213		5.8
Total	$	63,280	$	(1,267	)	$	62,013

Goodwill

Goodwill consists of the following:

	(in thousands)
Balance at December 31, 2019	$	14,608
Adjustment		—
Balance at December 31, 2020	$	14,608

No impairment has been recognized as of December 31, 2020. Goodwill recorded is not deductible for income tax purposes.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

8.	Commitments and contingencies

Leases

In January 2015, as amended in September 2016, the Company entered into an operating lease for approximately 42,000 square feet of office and laboratory space located at 700 Saginaw Drive, Redwood City, California (the 700 Building), with a term through April 2023. In April 2020, the Company amended the lease to lease an additional 19,000 square feet of office, laboratory and research and development space located at 300 Saginaw Drive, Redwood City, California (the 300 Building), beginning on December 15, 2020 and ending December 31, 2030, and to extend the Company’s existing lease term for the 700 Building until December 31, 2030. The Company has the option to extend the lease term for the 700 Building and the 300 Building together for an additional ten years after December 31, 2030.

The annual base rent for the lease of the 300 Building is $1.2 million until December 31, 2021, after which the annual base rent will increase by approximately 3.5% in each subsequent year of the lease term. The annual base rent for the lease of the 700 Building remains unchanged through April 30, 2023, and increases to $2.8 million for the 12 month period ending April 30, 2024, after which the annual base rent increases by approximately 3.5% in each subsequent year of the lease term.

In conjunction with the lease agreement, the Company paid a security deposit of $0.3 million which is included in other noncurrent assets on the consolidated balance sheets as of December 31, 2019 and 2018, respectively. In connection with the lease amendment the Company issued a letter of credit for $0.9 million, which is included in restricted cash on the consolidated balance sheet as of December 31, 2020.

Through December 31, 2020, the landlord has provided the Company with $3.4 million in tenant improvement allowances for the 700 Building, which were recognized as a lease incentive. The lease amendment provides the Company with an additional tenant improvement allowance for a total of $3.2 million to complete the renovation to the 300 building, which the Company has determined to be lessee owned. The lease incentive is being amortized as an offset to rent expense over the lease term in the consolidated statements of operations.

Upon the execution of the amendment, which was deemed to be a lease modification, the Company re-evaluated the assumptions used during the adoption of ASC 842 for the lease. The Company determined the amendment consists of two separate contracts under ASC 842. One contract is related to a new right-of-use asset for the 300 Building, which is being accounted for as a new operating lease, and the other is related to the modification of the original lease term for the original 700 Building. As a result, the Company recorded a right-of-use asset of $6.4 million and a lease liability of $9.0 million for the 300 Building and an increase of $14.8 million to the right-of-use asset and lease liability for the 700 Building upon the lease amendment. The Company is recognizing rent expense on a straight-line basis through the remaining extended term of the respective leases.

In July 2015, as amended in March 2016 and September 2016, the Company subleased a portion of the Redwood City Lease to Pliant Therapeutics, Inc., a related party, which expired in June 2018. Sublease income of zero, zero and $0.9 million for the years ended December 31, 2020, 2019 and 2018, respectively, was recorded as an offset to rent expense in the consolidated statements of operations.

As part of the Warp Drive acquisition in October 2018, the Company assumed an operating lease for approximately 22,000 square feet of office and laboratory space located in Cambridge, Massachusetts (Cambridge Lease), which expires in February 2023, with an option to extend the term through February 2028, subject to certain conditions. In March 2019, the Company fully subleased the Cambridge Lease to Casma Therapeutics, Inc. (Casma), a related party, on financial terms substantially the same as the original lease. The sublease term with Casma is through the remainder of the Cambridge Lease term. The sublease by Casma and related sublease payments by Casma to the Company are fully guaranteed by Third Rock Ventures, LLC, a related party. In conjunction with the Cambridge Lease, the Company issued a letter of credit for $0.2 million, which is included in restricted cash on the consolidated balance sheets as of December 31, 2020 and 2019.

The balance sheet classification of the Company’s lease liabilities was as follows:

	December 31, 2020
	(in thousands)
Operating lease liabilities:
Operating lease liability – current	$	3,672
Operating lease liability – noncurrent		28,992
Total operating lease liabilities		32,664
Financing lease liabilities:
Accrued expenses and other current liabilities		19
Total financing lease liabilities		19
Total lease liabilities	$	32,683

For the year ended December 31, 2020, operating lease cost was $2.7 million, net of sublease income of $1.9 million and tenant improvement allowance credits of $0.2 million. The operating cash flows for operating leases were $2.6 million year ended December 31, 2020. Short-term lease costs were immaterial for the year ended December 31, 2020.

As of December 31, 2020, the maturities of the Company’s operating lease liabilities were as follows (in thousands):


2021	$	4,381
2022		5,144
2023		4,173
2024		4,215
2025		4,363
Thereafter		24,213
Total undiscounted lease payments	$	46,489
Less: Imputed interest		(10,669	)
Less: Tenant improvement allowance		(3,156	)
Total operating lease liabilities	$	32,664

The amounts reflected in the table above include the Company’s lease payments for the Cambridge lease, but do not reflect any offset for the sublease payments the Company is entitled to receive from Casma. The amounts representing the tenant improvement allowance, which are recorded in prepaid expenses and other current assets, are expected to be fully received by the Company by the end of the first quarter of 2021.

Operating lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, the Company uses its incremental borrowing rate. The weighted-average discount rate used to determine the operating lease liability was 7.1%. As of December 31, 2020, the weighted-average remaining lease term is 9.1 years.

As of December 31, 2019, future minimum payments and receipts under the Company’s operating and capital leases and sublease, under the prior lease standard, ASC 840, were as follows:

	Gross lease commitments		Sublease income			Net lease commitments
	(in thousands)
2020	$	3,885	$	(1,701	)	$	2,184
2021		3,786		(1,752	)		2,034
2022		3,886		(1,804	)		2,082
2023		1,003		(302	)		701
Total future minimum lease payments	$	12,560	$	(5,559	)	$	7,001

Included in the amounts above are $0.2 million of capital lease obligations.

Rent expense under ASC840 for the years ended December 31, 2019 and 2018 was $2.0 million and $1.5 million, respectively, net of sublease income and tenant improvement allowance credits. The terms of the facility leases provide for rental payments on a graduated scale; however, rent expense was recognized on a straight-line basis over the lease term. As of December 31, 2019, $2.4 million was included as deferred rent, which includes the deferred tenant improvement allowance and straight-line rent. The current portion of deferred rent is included in accrued expenses and other current liabilities and the noncurrent portion of deferred rent is included in deferred rent, noncurrent on the consolidated balance sheets.

Legal matters

From time to time, the Company may be involved in litigation related to claims that arise in the ordinary course of its business activities. The Company accrues for these matters when it is probable that losses will be incurred and these losses can be reasonably estimated. As of December 31, 2020 and 2019, the Company does not believe that any such matters, individually or in the aggregate, will have a material adverse effect on the Company’s financial position, results of operations or cash flows.

Indemnification

The Company enters into standard indemnification arrangements in the ordinary course of business. Pursuant to these arrangements, the Company indemnifies, holds harmless and agrees to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, in connection with any trade secret, copyright, patent or other intellectual property infringement claim by any third party with respect to its technology. The term of these indemnification agreements is generally perpetual any time after the execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these arrangements is not determinable. The Company has not incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, the Company believes the fair value of these agreements is minimal.

Sanofi Collaboration Agreement

12 Months Ended

Dec. 31, 2020

Collaboration Agreement [Abstract]

Sanofi Collaboration Agreement

9.	Sanofi collaboration agreement

In June 2018, the Company entered into a collaborative research, development and commercialization agreement (the Sanofi Agreement) with Aventis, Inc. (an affiliate of Sanofi) to research and develop SHP2 inhibitors, including RMC-4630, for any indications. The Sanofi Agreement was assigned to Genzyme Corporation, a Sanofi affiliate, in December 2018. Pursuant to the Sanofi Agreement, the Company granted Sanofi a worldwide, exclusive, sublicensable (subject to the Company’s consent in certain circumstances) license under certain of the Company’s patents and know-how to research, develop, manufacture, use, sell, offer for sale, import and otherwise commercialize SHP2 inhibitors, including RMC-4630, for any and all uses, subject to the Company’s exercise of rights and performance obligations under the Sanofi Agreement.

In October 2018, the Company acquired Warp Drive in exchange for issuance of shares of the Company’s Series B redeemable convertible preferred stock and payment of cash. Sanofi was a stockholder of Warp Drive and received the Company’s Series B redeemable convertible preferred stock during the transaction and accordingly became an investor and related party of the Company.

Under the Sanofi Agreement, the Company received a non-refundable, upfront cash payment of $50 million in July 2018 and could also receive up to $520 million in development and regulatory milestone payments, including up to $235 million upon the achievement of specified development milestones and up to $285 million upon the achievement of certain marketing approval milestones.

The Company has primary responsibility for early clinical development and for the manufacture of SHP2 inhibitors for Phase 1 and non-registrational Phase 2 clinical trials of RMC-4630 pursuant to an initial development plan. A joint research and development committee is responsible for preparing development plans for other SHP2 inhibitors approved by this committee for development, if any. Sanofi is responsible to reimburse the Company all internal and external costs and expenses to perform the Company’s activities under the development plans.

The Company is also primarily responsible for performing preclinical research on SHP2 inhibitors, pursuant to a research plan that is currently approved through 2021. The research plan and budget beyond 2021 will be determined by a joint research and development committee, over which Sanofi has final decision-making power subject to certain exceptions. Sanofi is responsible to reimburse the Company for all internal and external costs and expenses incurred to perform activities under the approved research plans, with the exception of internal and external research costs and expenses under the approved research plans for 2019 and 2020, for which Sanofi is obligated to reimburse the Company for 80% of such costs. The Company is responsible for 20% of all internal and external research costs incurred under the research plans for 2019 and 2020. Sanofi is responsible to reimburse the Company for all internal and external costs and expenses incurred under the research plan for 2021.

In the United States, the Company will share equally with Sanofi the profits and losses applicable to commercialization of SHP2 inhibitor products, pursuant to a profit/loss share agreement that the parties will negotiate based on key terms agreed in the Sanofi Agreement. On a product-by-product basis, Sanofi will also be required to pay the Company tiered royalties on annual net sales of each product outside the United States ranging from high single digit to mid-teen percentages.

Unless terminated earlier, the Sanofi Agreement will continue in effect until the later of the expiration of all of Sanofi’s milestone and royalty payment obligations and the expiration of the profit/loss share agreement. Sanofi may terminate the Sanofi Agreement in its entirety or on a country-by-country or product-by-product basis for any reason or for significant safety concerns, upon prior notice to the Company. Sanofi may terminate the Sanofi Agreement in its entirety upon a change of control in the Company, with prior notice. Either party may terminate the Sanofi Agreement if an undisputed material breach by the other party is not cured within a defined period of time, or immediately upon notice for insolvency-related events of the other party. The Company may terminate the Sanofi Agreement after a certain number of years if Sanofi develops a competing program without commencing a registrational clinical trial for a SHP2 inhibitor product candidate, and subject to certain other conditions. The Company may also terminate the Sanofi Agreement at any time, if Sanofi ceases certain critical activities for SHP2 inhibitor product candidates for more than a specified period of time, provided that such cessations of critical activity were not a result of certain specified factors, and subject to certain other conditions. Upon any termination of the Sanofi Agreement with respect to any product or country, all licenses to Sanofi with respect to such product or country shall automatically terminate and all rights generally revert back to the Company.

The Company identified the following promises in the agreement (1) the license related to SHP2 inhibitors, (2) the performance of research and development services for Phase 1 clinical studies and Phase 2 clinical trials that are non-registrational clinical trials and (3) the performance of manufacturing services for the non-registrational clinical trials. The Company determined that the license is not distinct from the services within the context of the agreement because the research, development and manufacturing significantly increase the utility of the intellectual property. The intellectual property (IP) related to SHP2 inhibitors, which is proprietary to the Company, is the foundation for the research and development activities. The manufacturing services are a necessary and integral part of the research and development services as they could only be conducted utilizing the outcomes of these services. Given the research and development services under the Sanofi Agreement are expected to involve significant further development of the initial IP, the Company has concluded that the research, development and manufacturing services are not distinct from the license, and thus the license, research and development services and manufacturing services are combined into a single performance obligation.

For revenue recognition purposes, the Company determined that the duration of the contract begins on the effective date of the Sanofi Agreement in July 2018 and ends upon completion of the non-registrational clinical trials. The contract duration is defined as the period in which parties to the contract have present enforceable rights and obligations. The Company analyzed the impact of Sanofi terminating the agreement prior to the completion of these trials and determined that there were significant economic costs to Sanofi for doing so.

The Company determined that the transaction price of the Sanofi Agreement was $196.1 million as of December 31, 2020. In order to determine the transaction price, the Company evaluated all the payments to be received during the duration of the contract. The Company determined that the $50.0 million upfront payment and $146.1 million of estimated variable consideration for expense reimbursements from Sanofi for agreed upon research and development services as of December 31, 2020 constituted consideration to be included in the transaction price, which is to be allocated to the combined performance obligation. Development and regulatory milestones under the Sanofi Agreement were considered but not included in the transaction price, as it is probable that a significant revenue reversal could occur if they were included. The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur.

The license, research, development and manufacturing services are combined as one performance obligation that will be performed over the duration of the contract, which is from the effective date of the Sanofi Agreement through to the completion of studies. The Company concluded that it would utilize a cost-based input method to measure proportional performance and to calculate the corresponding amount of revenue to recognize. In applying the cost-based input method of revenue recognition, the Company uses actual costs incurred relative to estimated costs to fulfill the combined performance obligation. These costs consist primarily of internal full-time equivalent efforts and third-party costs. Revenue is recognized based on actual costs incurred as a percentage of total estimated costs as the Company completes its performance obligations. The cumulative effect of revisions to estimated costs to complete the Company’s performance obligations will be recorded in the period in which changes are identified and amounts can be reasonably estimated.

During the years ended December 31, 2020, 2019 and 2018, the Company recognized $43.0 million, $50.0 million and $19.4 million of collaboration revenue associated with this agreement, respectively.

As of December 31, 2020 and 2019, $12.1 million and $17.1 million of deferred revenue, related party is classified as current and $8.5 million and $14.7 million is classified as noncurrent.

Redeemable Convertible Preferred Stock

12 Months Ended

Dec. 31, 2020

Temporary Equity Disclosure [Abstract]

Redeemable Convertible Preferred Stock

10.	Redeemable convertible preferred stock

From December 2014 to May 2017, the Company issued a total of 14,430,799 shares of Series A redeemable convertible preferred stock at a price per share of $4.87 for proceeds of $70.1 million, net of issuance costs.

In March and June 2018, the Company issued a total of 7,731,155 shares of Series B redeemable convertible preferred stock at a price per share of $7.30 for proceeds of $56.2 million, net of issuance costs. In October 2018, the Company issued 6,797,915 shares of Series B redeemable convertible preferred stock in conjunction with acquiring Warp Drive. As part of the Warp Drive acquisition, the Company assumed $2.0 million in convertible notes payable, which was fully converted into 200,493 shares of Series B redeemable convertible preferred stock in October 2018. In November 2018, the Company issued 435,547 shares of Series B redeemable convertible preferred stock at a price per share of $10.03 for proceeds of $4.3 million, net of issuance costs.

In June and July 2019, the Company issued a total 10,004,514 shares of Series C redeemable convertible preferred stock at a price per share of $10.03 for proceeds of $100.0 million, net of issuance costs.

Redeemable convertible preferred stock consists of the following as of December 31, 2019:

	As of December 31, 2019
	Shares Authorized		Shares issued and outstanding		Net carrying value		Aggregate liquidation preference
	(in thousands, except share data)
Series A		70,221,732		14,430,799	$	72,248	$	84,865
Series B		74,000,000		15,165,110		132,833		120,152
Series C		48,683,038		10,004,514		100,028		103,671
Total		192,904,770		39,600,423	$	305,109	$	308,688

Upon the closing of the IPO in February 2020, all shares of redeemable convertible preferred stock then outstanding converted into 39,600,423 shares of common stock. There were no shares of redeemable convertible preferred stock outstanding as of December 31, 2020.

The redeemable convertible preferred stock was recorded outside of permanent equity because while it was not mandatorily redeemable, it would have become redeemable upon the occurrence of certain liquidation events that are considered not solely within the Company’s control. Accordingly, the redeemable convertible preferred stock has been presented in the mezzanine section on the consolidated balance sheets.

The holders of the Company’s redeemable convertible preferred stock had various rights, preferences, and privileges as follows:

Conversion rights

Each share of redeemable convertible preferred stock were convertible, at the option of the holder, into such number of fully paid shares of common stock as were determined by dividing the original issue price by the conversion price in effect at the time of conversion. As of December 31, 2019, the initial conversion price per share of redeemable convertible preferred stock were equivalent to the original issue price. The original issuance price was $4.87 per share for the Series A redeemable convertible preferred stock, $7.30 per share for the Series B redeemable convertible preferred stock and $10.03 for the Series C redeemable convertible preferred stock.

The respective applicable conversion price were subject to adjustment upon any future stock splits or stock combinations, reclassifications or exchanges of similar stock, upon a reorganization, recapitalization, merger or consolidation of the Company, or upon the issuance or sale by the Company of common stock for consideration less than the applicable conversion price.

Each share of Series A, B and C redeemable convertible preferred stock automatically converted into the number of shares of common stock determined in accordance with the conversion rate upon the earlier of (a) written consent of a majority of the then outstanding shares of Series A, B and C redeemable convertible preferred stock, voting together as a single class, or (b) the closing of a public offering in which the gross cash proceeds were at least $50.0 million and the minimum IPO price was $10.03 per share of common stock, subject to adjustment for stock dividends, stock splits, combinations or other similar recapitalizations.

Dividends

The holders of the outstanding shares of each series of redeemable convertible preferred stock were entitled to receive, when and if declared by the Board of Directors, a cumulative cash dividend at the rate of 6% of the applicable original issue price per annum on each outstanding share of redeemable convertible preferred stock. Such dividends were payable in preference to any dividends for common stock declared by the Board of Directors. In the case of a dividend on common stock, the dividend per share of redeemable convertible preferred stock would also include the dividend payable on each share determined, if applicable, as if all redeemable convertible preferred stock had been converted to common stock. No dividends had been declared or paid to holders of redeemable convertible preferred stock as of December 31, 2020.

Liquidation

In the event of any liquidation, dissolution, winding up, or deemed liquidation event of the Company, either voluntary or involuntary, the holders of redeemable convertible preferred stock were be entitled to receive pro rata, prior and in preference to any distribution to the holders of the common stock, an amount equal to the original issuance prices of each series (in each case, as adjusted for stock splits, stock dividends or distributions, recapitalizations, and similar events) and all declared but unpaid dividends, if any. If the assets and funds to be distributed among the holders of redeemable convertible preferred stock were insufficient to permit the payment to such holders, then the entire assets and funds of the Company legally available for distribution would be distributed ratably among the holders of redeemable convertible preferred stock in proportion to the preferential amount each such holder were otherwise entitled to receive.

Upon the payment of the full liquidation preference of redeemable convertible preferred stock, the remaining assets of the Company, if any, would be distributed ratably to the holders of common stock.

Voting rights

Each share of redeemable convertible preferred stock had a number of votes equal to the number of shares of common stock into which it was convertible. The holders of Series A redeemable convertible preferred stock had the right to elect two members of the Company’s Board of Directors. The holders of Series B redeemable convertible preferred stock had the right to elect one member of the Company’s Board of Directors. The holders of common stock had the right to elect one member of the Company’s Board of Directors. The holders of common stock and redeemable convertible preferred stock, voting together as a single class on an as-converted basis, were entitled to elect one member of the Board of Directors.

Common Stock

12 Months Ended

Dec. 31, 2020

Stockholders Equity Note [Abstract]

Common Stock

11.	Common stock

As of December 31, 2020 and 2019, the Company’s certificate of incorporation authorized the Company to issue 300,000,000 shares and 249,000,000 shares of common stock, respectively, at a par value of $0.0001 per share. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the Board of Directors, subject to prior rights of the redeemable convertible preferred stockholders. As of December 31, 2020, no dividends have been declared to date.

The Company has reserved shares of common stock, on an as-converted basis, for future issuance as follows:

	December 31,
	2020		2019
Redeemable convertible preferred stock		—		39,600,423
Outstanding options to purchase common stock		5,118,979		4,918,299
Unvested restricted stock units of common stock		85,639		—
Available for future issuance under the 2020 Incentive Award Plan		4,806,916		—
Available for issuance under the 2020 Employee Stock Purchase Plan		499,722		—
Available for future issuance under the 2014 Equity Incentive Plan		—		803,652
Total		10,511,256		45,322,374

Stock-Based Compensation

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

12.	Stock-based compensation

2020 Incentive Award Plan

In February 2020, the Company adopted the 2020 Equity Incentive Plan (2020 Plan). The 2020 Plan became effective on February 11, 2020. The 2020 Plan provides for a variety of stock-based compensation awards, including stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance bonus awards, performance stock unit awards, dividend equivalents, or other stock or cash based awards. Under the 2020 Plan, the Company generally grants stock-based awards with service-based vesting conditions only. Options and restricted stock unit awards granted typically vest over a four-year period, but may be granted with different vesting terms.

Following the effectiveness of the 2020 Plan, the Company will not make any further grants under the 2014 Equity Incentive Plan (2014 Plan). However, the 2014 Plan will continue to govern the terms and conditions of the outstanding awards granted under it. Shares of common stock subject to awards granted under the 2014 Plan that are forfeited or lapse unexercised and which following the effective date of the 2020 Plan are not issued under the 2014 Plan will be available for issuance under the 2020 Plan.

As of December 31, 2020, there were 4,806,916 shares of common stock reserved for issuance pursuant to the 2020 Plan.

2014 Equity Incentive Plan

In December 2014, the Company adopted the 2014 Plan which provided for the Company to issue restricted common stock, or to grant incentive stock options or nonqualified stock options for the purchase of common stock, to employees, members of the Board of Directors and consultants of the Company under terms and provisions established by the Board of Directors. The Company generally granted stock-based awards with service-based vesting conditions only. Options granted typically vest over a four-year period but may be granted with different vesting terms.

The Company allows its employees, non-employees and directors to exercise options granted under the 2014 Plan prior to vesting. The shares related to early exercised stock options are subject to the Company’s lapsing repurchase right upon termination of employment at the original purchase price. In order to vest, the holders are required to provide continued service to the Company. The proceeds are initially recorded in other noncurrent liabilities and are reclassified to common stock and additional paid-in capital as the repurchase right lapses. As of December 31, 2020 and 2019, there were 130,793 and 349,501 shares, respectively, and $0.2 million and $0.3 million, respectively, recorded in other noncurrent liabilities, related to early exercised shares that were subject to repurchase.

2020 Employee Stock Purchase Plan

In February 2020, the Company adopted the 2020 Employee Stock Purchase Plan (2020 ESPP). Under the 2020 ESPP, employees have the ability to purchase shares of the Company’s common stock through payroll deductions at a discount during a series of offering periods of 24 months, each comprised of four six-month purchase periods. The purchase price will be the lower of 85% of the closing trading price per share of the Company’s common stock on the first day of an offering period in which an employee is enrolled or 85% of the closing trading price per share on the purchase date, which will occur on the last trading day of each purchase period.

The Company has reserved for issuance 528,959 shares of common stock pursuant to the 2020 ESPP. As of December 31, 2020, there have been 29,237 purchases under the 2020 ESPP. As of December 31, 2020, a total of 499,722 shares of common stock were available for future issuance under the ESPP. As of December 31, 2020, there was $1.5 million of unrecognized compensation cost related to the ESPP.

Stock options

The following summarizes option activity under both the 2020 Plan and the 2014 Plan:

	Number of Options			Weighted- average exercise price		Weighted- average remaining contractual term		Aggregate intrinsic value
						(in years)		(in thousands)
Balance, January 1, 2019		1,632,797		$	0.98		8.76	$	5,085
Options granted		3,516,276			4.73
Options exercised		(171,110	)		2.01
Options cancelled		(59,664	)		3.73
Balance, December 31, 2019		4,918,299		$	3.59		8.96	$	51,276
Options granted		967,874			23.33
Options exercised		(694,441	)		2.77
Options cancelled		(72,753	)		8.16
Balance, December 31, 2020		5,118,979		$	7.37		8.25	$	165,088
Options vested and expected to vest as of December 31, 2020		5,118,979		$	7.37		8.25	$	165,088
Options vested and exercisable as of December 31, 2020		1,966,195		$	4.08		7.75	$	69,825

The aggregate intrinsic values of options outstanding, exercisable, vested and expected to vest were calculated as the difference between the exercise price of the options and the estimated fair value of the Company’s common stock by the Board of Directors. The intrinsic value of the options exercised for the years December 31, 2020, 2019 and 2018 was $21.7 million, $0.4 million and $0.4 million, respectively.

During the years ended December 31, 2020, 2019 and 2018, the weighted-average grant-date fair value of options granted was $15.59, $4.43 and $1.90 per share, respectively. As of December 31, 2020, there was $22.1 million of unrecognized stock-based compensation expense related to unvested stock options that is expected to be recognized over a weighted-average period of 2.5 years.

The fair value of employee and director stock option awards was estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2020	2019	2018
Expected term (years)	6	5-6	5-6
Expected volatility	74-80%	76-82%	79-81%
Risk-free interest rate	0.2%-1.5%	1.6%-2.5%	2.5%-3.0%
Dividend yield	0%	0%	0%

Non-employee stock option awards were measured at fair value at each reporting period using a Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2020	2019	2018
Expected term (years)	6-10	6-10	7-10
Expected volatility	74-80%	79-83%	80%
Risk-free interest rate	1.2%-1.5%	1.6%-2.6%	2.9%-3.0%
Dividend yield	0%	0%	0%

The Black-Scholes model assumptions that determine the fair value of stock-based awards include:

Expected term—The expected term is calculated using the simplified method, which is available where there is insufficient historical data about exercise patterns and post-vesting employment termination behavior. The simplified method is based on the vesting period and the contractual term for each grant, or for each vesting-tranche for awards with graded vesting. The mid-point between the vesting date and the maximum contractual expiration date is used as the expected term under this method.

Expected volatility—Given the Company does not have sufficient trading history for its common stock, the expected volatility was estimated based on the average volatility for comparable publicly traded biotechnology companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on their similar size, stage in the life cycle or area of specialty.

Risk-free interest rate—The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of option.

Expected dividend—The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.

Restricted stock units

Restricted stock units (RSUs) have been granted to employees and directors. The value of an RSU award is based on the Company’s stock price on the date of grant. The shares underlying the RSU awards are not issued until the RSUs vest. Upon vesting, each RSU converts into one share of the Company’s common stock. The Company has granted RSUs pursuant to the 2020 plan.

Activity under the 2020 Plan with respect to the Company’s RSUs during the year ended December 31, 2020 was as follows:

	Number of Shares			Weighted- average grant date fair value per share		Weighted- average remaining contractual term		Aggregate intrinsic value
						(in years)		(in thousands)
Balance, December 31, 2019		—		$	—		—	$	—
Restricted stock units granted		87,520			35.12
Restricted stock units vested		(1,681	)		34.98
Restricted stock units forfeited		(200	)		30.96
Balance, December 31, 2020		85,639		$	35.13		1.73	$	3,390
Expected to vest as of December 31, 2020		85,639		$	35.13		1.73	$	3,390

The number of RSUs vested includes shares of common stock that the Company withheld to satisfy the minimum statutory tax withholding requirements. As of December 31, 2020, there was $2.7 million of total unrecognized compensation cost related to RSUs that is expected to be recognized over a weighted average period of 3.3 years.

The total fair value of RSUs vested for the years ended December 31, 2020, 2019 and 2018 was $0.1 million, zero and zero, respectively.

Stock-based compensation expense

Total stock-based compensation expense related to stock options, RSUs and the 2020 ESPP by function was as follows:

	Year Ended December 31,
	2020		2019		2018
	(in thousands)
Research and development	$	4,848	$	1,789	$	563
General and Administrative		4,038		1,372		292
Total	$	8,886	$	3,161	$	855

Stock-based compensation related to options granted to non-employees was $0.8 million, $0.7 million and $0.3 million for the years ended December 31, 2020, 2019 and 2018, respectively.

Restricted stock

In 2014, the Company issued restricted stock awards to employees and directors under the 2014 Plan at a purchase price of $0.0001 per share. The shares related to restricted stock awards vest over a four-year period and are subject to a lapsing repurchase right upon termination of employment at the original purchase price. Recipients of restricted stock awards have voting and dividend rights with respect to such shares upon grant without regard to vesting. All restricted stock awards were vested as of December 31, 2020 and 2019, respectively.

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

13.	Income taxes

The Company recorded an income tax benefit of $0.4 million and $4.4 million for the years ended December 31, 2020 and 2019, respectively, which reflects a change in the valuation allowance relating to the acquisition of Warp Drive Bio in 2018. The Company has incurred net pre-tax losses in the United States only for all periods presented. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to the differences between the carrying amounts of existing assets and liabilities in the financial statements and their respective tax bases using tax rates expected to be in effect during the years in which the basis differences reverse.

The benefit from income taxes differs from the amount expected by applying the federal statutory rate to the loss before taxes as follows:

	Year Ended December 31,
	2020			2019
Federal statutory income tax rate		21.0	%		21.0	%
State income tax rate, net of federal benefit		9.7			10.7
Research tax credits		3.3			1.0
Change in valuation allowance		(34.3	)		(24.2	)
Non-deductible permanent expenses		0.9			(0.5	)
Other		(0.3	)		0.4
Benefit from income taxes		0.3	%		8.4	%

Deferred income tax reflects the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The categories that give rise to significant components of the deferred tax assets are as follows (in thousands):

	December 31,
	2020			2019
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	74,137		$	38,511
Accruals and reserves		8,505			11,927
Research and development credits		10,346			6,764
Lease liability		9,845			—
Stock-based compensation		1,241			1,021
Other		38			38
Gross deferred tax assets		104,112			58,261
Less: valuation allowance		(84,680	)		(47,426	)
Total deferred tax assets		19,432			10,835
Deferred tax liabilities:
Fixed assets and finite-lived intangible assets		(10,397	)		(10,836	)
Indefinite-lived intangible assets		(7,444	)		(7,818	)
Lease asset		(766	)		—
Right-of-use asset		(8,269	)		—
Gross deferred tax liabilities		(26,876	)		(18,654	)
Net deferred tax liability	$	(7,444	)	$	(7,819	)

The realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Due to the lack of earnings history, the net deferred tax assets have been offset by a valuation allowance. The valuation allowance increased by $37.3 million and $12.6 million during the years ended December 31, 2020 and 2019, respectively. The Company had net operating loss carryforwards for federal, California, Massachusetts, and New Jersey income tax purposes of $265.8 million, $52.7 million, $55.0 million and $163.4 million, respectively, as of December 31, 2020. The federal, California and Massachusetts net operating loss carryforwards, if not utilized, will expire beginning in 2035, with the exception of $172.1 million in federal net operating loss carryforwards, which can be carried forward indefinitely. New Jersey net operating loss carryforwards, if not utilized, will expire beginning in 2039. Under the Tax Act, federal net operating losses arising after December 31, 2017 do not expire and cannot be carried back. However, the TJCA limits the amount of federal net operating losses that can be used annually to 80% of taxable income for periods beginning after December 31, 2017. Existing federal net operating losses arising in years ending on or before December 31, 2017 are not affected by these provisions.

The Company also had federal and state research and development credit carryforwards of $9.0 million and $5.8 million, respectively, as of December 31, 2020. The federal credits will expire starting in 2034 if not utilized and the state research credits will expire beginning in 2031, with the exception of $5.0 million in California research credits, which can be carried forward indefinitely. Federal, California, Massachusetts and New Jersey tax laws impose significant restrictions on the utilization of net operating loss carryforwards in the event of a change in ownership of the Company, as defined by Internal Revenue Code Section 382 (Section 382). The Company performed a study in which it determined that it had experienced changes in ownership in December 2014, June 2018, and March 2020 as defined by Section 382. No federal or state net operating losses are expected to expire unutilized as a result of the limitation, with the exception of $5.5 million in California net operating losses. In addition, in the future the Company may experience ownership changes, which may limit the utilization of net operating loss carryforwards or other tax attributes.

A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:

	December 31,
	2020			2019
	(in thousands)
Beginning balance	$	2,419		$	2,441
Changes related to tax positions taken in the prior year		(41	)		(567	)
Changes related to tax positions taken in current year		1,215			545
Ending balance	$	3,593		$	2,419

The Company has unrecognized tax benefits of $2.2 million and $3.3 million as of December 31, 2019 and 2020, which would affect the effective tax rate if recognized; however, recognition would be in the form of a deferred tax attribute which would likely be offset by a valuation allowance. The Company does not anticipate any significant changes to unrecognized tax benefits over the next 12 months. The Company has recognized no interest or penalties related to uncertain tax positions for the periods presented.

Income tax returns are filed in the United States, California, Massachusetts and New Jersey. The years 2010 through 2020 remain open to examination by the domestic taxing jurisdictions to which the Company is subject. Net operating losses generated on a tax return basis by the Company for 2010 through 2020 remain open to examination by the domestic taxing jurisdictions.

On March 27, 2020 and December 27, 2020, the United States enacted the Coronavirus Aid, Relief, and Economic Security (CARES) Act and the Consolidated Appropriation Act (CAA), respectively, as a result of the Coronavirus pandemic, which contain among other things, numerous income tax provisions. Some of these tax provisions are expected to be effective retroactively for years ending before the date of enactment. The Company has evaluated the current legislation and at this time, does not anticipate the CARES Act or the CCA to have a material impact on its financial statements.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Net Loss Per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

14.	Net loss per share attributable to common stockholders

The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders:

	Year ended December 31,
	2020			2019			2018
	(in thousands, except share and per share data)
Numerator:
Net loss	$	(108,159	)	$	(47,664	)	$	(41,789	)
Redeemable convertible preferred stock dividends- undeclared and cumulative		(2,219	)		(14,238	)		(7,031	)
Net loss attributable to common stockholders	$	(110,378	)	$	(61,902	)	$	(48,820	)
Denominator:
Weighted-average shares outstanding		55,109,929			3,231,389			3,140,848
Less: Weighted-average unvested restricted shares and shares subject to repurchase		(235,810	)		(458,800	)		(842,028	)
Weighted-average shares used to compute net loss per share attributable to common stockholders-basic and diluted		54,874,119			2,772,589			2,298,820
Net loss per share attributable to common stockholders-basic and diluted	$	(2.01	)	$	(22.33	)	$	(21.24	)

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:

	Year ended December 31,
	2020		2019		2018
Redeemable convertible preferred stock		—		39,600,423		29,595,909
Options to purchase common stock		5,118,979		4,918,299		1,632,797
Options early exercised subject to future vesting		130,793		349,501		615,742
Unvested restricted stock units of common stock		85,639		—		—
Expected shares to be purchased under ESPP		91,210		—		—
Total		5,426,621		44,868,223		31,844,448

Related Party Relationships

12 Months Ended

Dec. 31, 2020

Related Party Relationships

15.	Related party relationships

In October 2018, the Company acquired all outstanding shares of Warp Drive Bio, Inc. (Warp Drive). In connection with the acquisition, the Company issued 6,797,915 shares of Series B redeemable convertible preferred stock (the Acquisition Shares). Of the Acquisition Shares, 1,708,824 shares of Series B redeemable convertible preferred stock were issued to entities affiliated with Third Rock Ventures, a related party. In addition, Alexis Borisy, who is currently a member of the Company’s board of directors and was a member of the Company’s board of directors at the time of the acquisition of Warp Drive, was then an affiliate of Third Rock Ventures. Of the Acquisition Shares, 3,363,050 shares of Series B redeemable convertible preferred stock were issued to Sanofi, which became a related party following the acquisition. See Note 9, “Sanofi collaboration agreement,” for a discussion of the Sanofi collaboration agreement.

In connection with the Company’s acquisition of Warp Drive, the Company assumed a Convertible Note issued by Warp Drive to an entity affiliated with Third Rock Ventures, dated October 8, 2018. The Convertible Note was issued in a principal amount of $2.0 million, with interest at an annual rate of 8% computed on the basis of a 360-day year. On October 30, 2018, at the Company’s election, the Company converted the Convertible Note into 200,493 shares of Series B redeemable convertible preferred stock which were issued to an entity affiliated with Third Rock Ventures pursuant to the terms of the Convertible Note.

Following the Company’s acquisition of Warp Drive, in January 2019, the Company entered into a sublease agreement with Casma to sublease the Cambridge Lease. The sublease by Casma and related sublease payments by Casma to the Company are fully guaranteed by an affiliate of Third Rock Ventures.

From July 2015 to June 2018, the Company subleased a portion of its Redwood City Lease to Pliant Therapeutics, Inc., an entity affiliated with Third Rock Ventures.

In connection with the Company’s obligations and responsibilities under the Sanofi Agreement, in April 2019, the Company entered into a Clinical Supply Agreement with Genzyme Corporation (Genzyme), an affiliate of Sanofi, and a Quality Agreement with Sanofi-Aventis Recherche & Developpement, an affiliate of Sanofi. The Quality Agreement was amended in December 2019. Sanofi was a related party at the time both agreements were entered into. The Clinical Supply Agreement governs how the Company will oversee the manufacture and supply of any SHP2 inhibitors requested by Genzyme for use in its clinical development activities under the Sanofi Agreement and provides that Genzyme will compensate the Company for the costs to manufacture any such product plus a 10% fee. The Quality Agreement requires that the production of RMC-4630 meets certain quality standards and puts certain conditions on the Company’s arrangements with subcontractors. The Quality Agreement does not contemplate that any consideration be paid separate from the Sanofi Agreement.

Subsequent Events

12 Months Ended

Dec. 31, 2020

Subsequent Events [Abstract]

Subsequent Events

16.	Subsequent events

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2020

Selected Quarterly Financial Information [Abstract]

Selected Quarterly Financial Data (Unaudited)

17.	Selected quarterly financial data (unaudited)

	Quarter Ended
	March 31, 2020			June 30, 2020			September 30, 2020			December 31, 2020
	(unaudited, in thousands, except per share data)
Revenue	$	11,546		$	10,025		$	12,661		$	8,751
Net loss	$	(19,519	)	$	(27,215	)	$	(27,221	)	$	(34,204	)
Net loss per share attributable to common stockholders - basic and diluted	$	(0.74	)	$	(0.46	)	$	(0.42	)	$	(0.52	)

	Quarter Ended
	March 31, 2019			June 30, 2019			September 30, 2019			December 31, 2019
	(unaudited, in thousands, except per share data)
Revenue	$	13,166		$	12,281		$	12,506		$	12,088
Net loss	$	(10,131	)	$	(10,119	)	$	(12,818	)	$	(14,596	)
Net loss per share attributable to common stockholders - basic and diluted	$	(4.84	)	$	(4.85	)	$	(6.08	)	$	(6.48	)

Net loss per common share attributable to common stockholders, basic and diluted, for the four quarters of each fiscal year may not sum to the total for the fiscal year because of the different number of shares outstanding during each period

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Basis of Presentation

Basis of presentation

Reverse Stock Split

Reverse stock split

Use of Estimates

Use of estimates

Cash and Cash Equivalents

Cash and cash equivalents

Marketable Securities

Marketable securities

Restricted Cash

Restricted cash

Concentration of Credit Risk and Other Risks and Uncertainties

Concentration of credit risk and other risks and uncertainties

Fair Value Measurement

Fair value measurement

Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Property and Equipment, Net

Property and equipment, net

Useful lives of property and equipment are as follows:

Property and equipment		Estimated useful life
Laboratory equipment		4-5 years
Leasehold improvements		Lesser of estimated useful life or remaining lease term
Computer equipment and software		3 years
Furniture and fixtures		5 years

Leases

Impairment of Long-Lived Assets

Impairment of long-lived assets

Acquired Intangible Assets

Acquired intangible assets

Goodwill

Redeemable Convertible Preferred Stock

Redeemable convertible preferred stock

Redeemable Convertible Preferred Stock Liability

Redeemable convertible preferred stock liability

Revenue Recognition

Revenue recognition

Research and Development Expenditures

Research and development expenditures

Stock-Based Compensation

Stock-based compensation

Comprehensive Loss

Comprehensive loss

Income Taxes

Income taxes

Net Loss per Share Attributable to Common Stockholders

Net loss per share attributable to common stockholders

Deferred Offering Costs

Deferred offering costs

Segment Reporting

Segment reporting

Retirement Plans

Retirement plans

Recently Adopted Accounting Pronouncements

Recent accounting pronouncements

Recently adopted accounting pronouncements

Recent Accounting Pronouncements Not Yet Adopted

Recent accounting pronouncements not yet adopted

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Schedule of Useful Lives of Property and Equipment

Useful lives of property and equipment are as follows:

Property and equipment		Estimated useful life
Laboratory equipment		4-5 years
Leasehold improvements		Lesser of estimated useful life or remaining lease term
Computer equipment and software		3 years
Furniture and fixtures		5 years

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Financial Assets Measured at Fair Value

The following table presents information about the Company’s financial assets that are measured at fair value and indicates the fair value hierarchy of the valuation:

	December 31, 2020
	Total		Level 1		Level 2		Level 3
	(in thousands)
Assets:
Money market funds ⁽¹⁾	$	16,696	$	16,696	$	—	$	—
Commercial paper ^{(1, 2)}		151,663		—		151,663		—
U.S. government and agency securities^{(1, 2)}		270,520		—		270,520		—
Corporate bonds ^{(1, 2)}		3,200		—		3,200		—
Total	$	442,079	$	16,696	$	425,383	$	—

	December 31, 2019
	Total		Level 1		Level 2		Level 3
	(in thousands)
Assets:
Money market funds ⁽¹⁾	$	9,369	$	9,369	$	—	$	—
Commercial paper ⁽²⁾		32,597		—		32,597		—
U.S. government and agency securities⁽²⁾		42,814		—		42,814		—
Corporate bonds ⁽²⁾		38,837		—		38,837		—
Total	$	123,617	$	9,369	$	114,248	$	—

(1)Included in cash and cash equivalents on the consolidated balance sheets.

(2)Included in marketable securities on the consolidated balance sheets.

Available-for-sale Securities (Tables)

12 Months Ended

Dec. 31, 2020

Investments Debt And Equity Securities [Abstract]

Summary of Estimated Value of Available-for-sale Securities and Cash Equivalents and Gross Unrealized Gains and Losses

The following tables summarize the estimated value of the Company’s available-for-sale marketable securities and cash equivalents and the gross unrealized gains and losses:

	December 31, 2020
			Gross		Gross
	Amortized		unrealized		unrealized			Estimated
	cost		gain		loss			fair value
	(in thousands)
Marketable securities:
Commercial paper	$	69,871	$	—	$	(5	)	$	69,866
U.S. government and agency securities		266,481		131		(5	)		266,607
Total marketable securities		336,352		131		(10	)		336,473
Cash equivalents:
Money market funds		16,696		—		—			16,696
Commercial paper		81,800		—		(3	)		81,797
U.S. government and agency securities		3,913		—		—			3,913
Corporate bonds		3,202		—		(2	)		3,200
Total cash equivalents		105,611		—		(5	)		105,606
Total available-for-sale investments	$	441,963	$	131	$	(15	)	$	442,079

	December 31, 2019
			Gross		Gross
	Amortized		unrealized		unrealized			Estimated
	cost		gain		loss			fair value
	(in thousands)
Marketable securities:
Commercial paper	$	24,446	$	3	$	(1	)	$	24,448
U.S. government and agency securities		42,777		39		(2	)		42,814
Corporate bonds		38,802		37		(2	)		38,837
Total marketable securities		106,025		79		(5	)		106,099
Cash equivalents:
Money market funds		9,369		—		—			9,369
Commercial paper		8,149		—		—			8,149
Total cash equivalents		17,518		—		—			17,518
Total available-for-sale investments	$	123,543	$	79	$	(5	)	$	123,617

Summary of Amortized Cost and Estimated Fair Value of Available-for-sale Securities and Cash Equivalents by Contractual Maturity

The amortized cost and estimated fair value of the Company’s available-for-sale marketable securities and cash equivalents by contractual maturity are summarized below as of December 31, 2020:

	December 31, 2020
			Gross		Gross
	Amortized		unrealized		unrealized			Estimated
	cost		gain		loss			fair value
	(in thousands)
Mature in one year or less	$	409,968	$	127	$	(15	)	$	410,080
Mature after one year through two years		31,995		4		—			31,999
Total marketable securities	$	441,963	$	131	$	(15	)	$	442,079

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2020

Balance Sheet Related Disclosures [Abstract]

Schedule of Property and Equipment, Net

Property and equipment, net consists of the following:

	December 31,
	2020			2019
	(in thousands)
Laboratory equipment	$	9,978		$	8,032
Leasehold improvements		3,387			3,342
Computer equipment and software		1,578			1,284
Furniture and fixtures		48			48
Construction in progress		1,981			—
		16,972			12,706
Less: accumulated depreciation and amortization		(8,070	)		(5,559	)
Property and equipment, net	$	8,902		$	7,147

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:

	December 31,
	2020		2019
	(in thousands)
Accrued compensation	$	7,736	$	4,069
Accrued research and development		10,459		7,195
Deferred rent, current		—		609
Accrued professional services		492		1,607
Other		97		1,048
Total accrued expenses and other current liabilities	$	18,784	$	14,528

Acquisition of Warp Drive (Tables)

12 Months Ended

Dec. 31, 2020

Business Combinations [Abstract]

Summary of Purchase Price Consideration For Acquisition

The following table presents a summary of the purchase price consideration for the acquisition:

	(in thousands)
Series B redeemable convertible preferred stock	$	68,144
Cash		1,172
Contingently returnable consideration asset		(310	)
Total consideration	$	69,006

Summary of Fair Values of Assets Acquired and Liabilities Assumed at Acquisition Date

The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date:

	(in thousands)
Assets acquired:
Cash and other current assets	$	1,594
Property and equipment		2,151
In-process research and development - RAS programs		55,800
Developed technology - tri-complex platform		7,480
Developed technology - genome mining platform		6,100
Total assets acquired		73,125
Liabilities assumed:
Accounts payable and other accrued liabilities		3,790
Convertible note payable, related party		2,000
Deferred revenue		745
Deferred tax liability		12,192
Total liabilities assumed		18,727
Goodwill		14,608
Total	$	69,006

Summary of Proforma Financial Information of Acquisition

	Year Ended December 31,
	2018
	(unaudited, in thousands)
Revenue	$	20,302
Net loss		(57,151	)

Intangible Assets and Goodwill (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets, Net

Intangible assets, net consist of the following as of December 31, 2020:

	Gross value		Accumulated amortization			Net book value		Weighted- average remaining useful life
	(in thousands)							(in years)
In-process research and development - RAS Programs	$	55,800	$	—		$	55,800	n/a
Developed technology - tri-complex platform		7,480		(2,335	)		5,145		4.8
Total	$	63,280	$	(2,335	)	$	60,945

Intangible assets, net consist of the following as of December 31, 2019:

	Gross value		Accumulated amortization			Net book value		Weighted- average remaining useful life
	(in thousands)							(in years)
In-process research and development - RAS Programs	$	55,800	$	—		$	55,800	n/a
Developed technology - tri-complex platform		7,480		(1,267	)		6,213		5.8
Total	$	63,280	$	(1,267	)	$	62,013

Schedule of Future Amortization Expense

As of December 31, 2020, future amortization expense is as follows:

	Amount
	(in thousands)
2021		1,069
2022		1,069
2023		1,069
2024		1,069
2025		869
Total	$	5,145

Schedule of Goodwill

Goodwill consists of the following:

	(in thousands)
Balance at December 31, 2019	$	14,608
Adjustment		—
Balance at December 31, 2020	$	14,608

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2020

Commitments And Contingencies Disclosure [Abstract]

Summary of Balance Sheet Classification of Lease Liabilities

The balance sheet classification of the Company’s lease liabilities was as follows:

	December 31, 2020
	(in thousands)
Operating lease liabilities:
Operating lease liability – current	$	3,672
Operating lease liability – noncurrent		28,992
Total operating lease liabilities		32,664
Financing lease liabilities:
Accrued expenses and other current liabilities		19
Total financing lease liabilities		19
Total lease liabilities	$	32,683

Schedule of Maturities of Operating Lease Liabilities

As of December 31, 2020, the maturities of the Company’s operating lease liabilities were as follows (in thousands):


2021	$	4,381
2022		5,144
2023		4,173
2024		4,215
2025		4,363
Thereafter		24,213
Total undiscounted lease payments	$	46,489
Less: Imputed interest		(10,669	)
Less: Tenant improvement allowance		(3,156	)
Total operating lease liabilities	$	32,664

Schedule of Future Minimum Payment and Receipts Under Operating and Capital Lease and Sublease

As of December 31, 2019, future minimum payments and receipts under the Company’s operating and capital leases and sublease, under the prior lease standard, ASC 840, were as follows:

	Gross lease commitments		Sublease income			Net lease commitments
	(in thousands)
2020	$	3,885	$	(1,701	)	$	2,184
2021		3,786		(1,752	)		2,034
2022		3,886		(1,804	)		2,082
2023		1,003		(302	)		701
Total future minimum lease payments	$	12,560	$	(5,559	)	$	7,001

Redeemable Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2020

Temporary Equity Disclosure [Abstract]

Schedule of Redeemable Convertible Preferred Stock

Redeemable convertible preferred stock consists of the following as of December 31, 2019:

	As of December 31, 2019
	Shares Authorized		Shares issued and outstanding		Net carrying value		Aggregate liquidation preference
	(in thousands, except share data)
Series A		70,221,732		14,430,799	$	72,248	$	84,865
Series B		74,000,000		15,165,110		132,833		120,152
Series C		48,683,038		10,004,514		100,028		103,671
Total		192,904,770		39,600,423	$	305,109	$	308,688

Common Stock (Tables)

12 Months Ended

Dec. 31, 2020

Stockholders Equity Note [Abstract]

Schedule of Common Stock Reserved on Converted Basis for Future Issuance

The Company has reserved shares of common stock, on an as-converted basis, for future issuance as follows:

	December 31,
	2020		2019
Redeemable convertible preferred stock		—		39,600,423
Outstanding options to purchase common stock		5,118,979		4,918,299
Unvested restricted stock units of common stock		85,639		—
Available for future issuance under the 2020 Incentive Award Plan		4,806,916		—
Available for issuance under the 2020 Employee Stock Purchase Plan		499,722		—
Available for future issuance under the 2014 Equity Incentive Plan		—		803,652
Total		10,511,256		45,322,374

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of Fair Value of Stock Option Awards Estimated at Date of Grant

The fair value of employee and director stock option awards was estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2020	2019	2018
Expected term (years)	6	5-6	5-6
Expected volatility	74-80%	76-82%	79-81%
Risk-free interest rate	0.2%-1.5%	1.6%-2.5%	2.5%-3.0%
Dividend yield	0%	0%	0%

Non-employee stock option awards were measured at fair value at each reporting period using a Black-Scholes option-pricing model with the following assumptions:

	Year Ended December 31,
	2020	2019	2018
Expected term (years)	6-10	6-10	7-10
Expected volatility	74-80%	79-83%	80%
Risk-free interest rate	1.2%-1.5%	1.6%-2.6%	2.9%-3.0%
Dividend yield	0%	0%	0%

Summary of Total Stock-Based Compensation Expense Related to Stock Options, RSUs and Employee Stock Purchase Plan

Total stock-based compensation expense related to stock options, RSUs and the 2020 ESPP by function was as follows:

	Year Ended December 31,
	2020		2019		2018
	(in thousands)
Research and development	$	4,848	$	1,789	$	563
General and Administrative		4,038		1,372		292
Total	$	8,886	$	3,161	$	855

2020 Plan and 2014 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of Option Activity Under the Plan

The following summarizes option activity under both the 2020 Plan and the 2014 Plan:

	Number of Options			Weighted- average exercise price		Weighted- average remaining contractual term		Aggregate intrinsic value
						(in years)		(in thousands)
Balance, January 1, 2019		1,632,797		$	0.98		8.76	$	5,085
Options granted		3,516,276			4.73
Options exercised		(171,110	)		2.01
Options cancelled		(59,664	)		3.73
Balance, December 31, 2019		4,918,299		$	3.59		8.96	$	51,276
Options granted		967,874			23.33
Options exercised		(694,441	)		2.77
Options cancelled		(72,753	)		8.16
Balance, December 31, 2020		5,118,979		$	7.37		8.25	$	165,088
Options vested and expected to vest as of December 31, 2020		5,118,979		$	7.37		8.25	$	165,088
Options vested and exercisable as of December 31, 2020		1,966,195		$	4.08		7.75	$	69,825

2020 Equity Incentive Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of RSUs Activity Under the Plan

Activity under the 2020 Plan with respect to the Company’s RSUs during the year ended December 31, 2020 was as follows:

	Number of Shares			Weighted- average grant date fair value per share		Weighted- average remaining contractual term		Aggregate intrinsic value
						(in years)		(in thousands)
Balance, December 31, 2019		—		$	—		—	$	—
Restricted stock units granted		87,520			35.12
Restricted stock units vested		(1,681	)		34.98
Restricted stock units forfeited		(200	)		30.96
Balance, December 31, 2020		85,639		$	35.13		1.73	$	3,390
Expected to vest as of December 31, 2020		85,639		$	35.13		1.73	$	3,390

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Summary of Benefit from Income Taxes to Amount Computed by Applying Federal Statutory Rate to Loss Before Taxes

The benefit from income taxes differs from the amount expected by applying the federal statutory rate to the loss before taxes as follows:

	Year Ended December 31,
	2020			2019
Federal statutory income tax rate		21.0	%		21.0	%
State income tax rate, net of federal benefit		9.7			10.7
Research tax credits		3.3			1.0
Change in valuation allowance		(34.3	)		(24.2	)
Non-deductible permanent expenses		0.9			(0.5	)
Other		(0.3	)		0.4
Benefit from income taxes		0.3	%		8.4	%

Summary of Categories that Give Rise to Significant Components of Deferred Tax Assets

The categories that give rise to significant components of the deferred tax assets are as follows (in thousands):

	December 31,
	2020			2019
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	74,137		$	38,511
Accruals and reserves		8,505			11,927
Research and development credits		10,346			6,764
Lease liability		9,845			—
Stock-based compensation		1,241			1,021
Other		38			38
Gross deferred tax assets		104,112			58,261
Less: valuation allowance		(84,680	)		(47,426	)
Total deferred tax assets		19,432			10,835
Deferred tax liabilities:
Fixed assets and finite-lived intangible assets		(10,397	)		(10,836	)
Indefinite-lived intangible assets		(7,444	)		(7,818	)
Lease asset		(766	)		—
Right-of-use asset		(8,269	)		—
Gross deferred tax liabilities		(26,876	)		(18,654	)
Net deferred tax liability	$	(7,444	)	$	(7,819	)

Reconciliation of Gross Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:

	December 31,
	2020			2019
	(in thousands)
Beginning balance	$	2,419		$	2,441
Changes related to tax positions taken in the prior year		(41	)		(567	)
Changes related to tax positions taken in current year		1,215			545
Ending balance	$	3,593		$	2,419

Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders

The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders:

	Year ended December 31,
	2020			2019			2018
	(in thousands, except share and per share data)
Numerator:
Net loss	$	(108,159	)	$	(47,664	)	$	(41,789	)
Redeemable convertible preferred stock dividends- undeclared and cumulative		(2,219	)		(14,238	)		(7,031	)
Net loss attributable to common stockholders	$	(110,378	)	$	(61,902	)	$	(48,820	)
Denominator:
Weighted-average shares outstanding		55,109,929			3,231,389			3,140,848
Less: Weighted-average unvested restricted shares and shares subject to repurchase		(235,810	)		(458,800	)		(842,028	)
Weighted-average shares used to compute net loss per share attributable to common stockholders-basic and diluted		54,874,119			2,772,589			2,298,820
Net loss per share attributable to common stockholders-basic and diluted	$	(2.01	)	$	(22.33	)	$	(21.24	)

Schedule of Outstanding Potentially Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Share

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:

	Year ended December 31,
	2020		2019		2018
Redeemable convertible preferred stock		—		39,600,423		29,595,909
Options to purchase common stock		5,118,979		4,918,299		1,632,797
Options early exercised subject to future vesting		130,793		349,501		615,742
Unvested restricted stock units of common stock		85,639		—		—
Expected shares to be purchased under ESPP		91,210		—		—
Total		5,426,621		44,868,223		31,844,448

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2020

Selected Quarterly Financial Information [Abstract]

Summary of Quarterly Financial Data (Unaudited)

	Quarter Ended
	March 31, 2020			June 30, 2020			September 30, 2020			December 31, 2020
	(unaudited, in thousands, except per share data)
Revenue	$	11,546		$	10,025		$	12,661		$	8,751
Net loss	$	(19,519	)	$	(27,215	)	$	(27,221	)	$	(34,204	)
Net loss per share attributable to common stockholders - basic and diluted	$	(0.74	)	$	(0.46	)	$	(0.42	)	$	(0.52	)

	Quarter Ended
	March 31, 2019			June 30, 2019			September 30, 2019			December 31, 2019
	(unaudited, in thousands, except per share data)
Revenue	$	13,166		$	12,281		$	12,506		$	12,088
Net loss	$	(10,131	)	$	(10,119	)	$	(12,818	)	$	(14,596	)
Net loss per share attributable to common stockholders - basic and diluted	$	(4.84	)	$	(4.85	)	$	(6.08	)	$	(6.48	)

Organization - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Feb. 18, 2020	Feb. 28, 2021	Jul. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Accumulated deficit				$ 265,545	$ 157,386
Common stock, shares, issued				66,599,748	3,292,124
Net proceeds from issuance				$ 420,067
Initial Public Offering
Class Of Stock [Line Items]
Common stock, shares, issued	16,100,000
Common stock, price per share	$ 17.00
Net proceeds from issuance	$ 250,700
Underwriting discounts and commissions	19,200
Stock issuance expenses	$ 3,800
Underwriter's Option to Purchase Additional Shares
Class Of Stock [Line Items]
Common stock, shares, issued	2,100,000		900,000
Underwriter's Option to Purchase Additional Shares \| Subsequent Event
Class Of Stock [Line Items]
Common stock, shares, issued		869,565
Underwritten Public Offering
Class Of Stock [Line Items]
Common stock, shares, issued			6,900,000
Common stock, price per share			$ 26.00
Net proceeds from issuance			$ 167,800
Underwriting discounts and commissions			10,800
Stock issuance expenses			$ 800
Underwritten Public Offering \| Subsequent Event
Class Of Stock [Line Items]
Common stock, shares, issued		6,666,666
Common stock, price per share		$ 45.00
Net proceeds from issuance		$ 281,300

Summary of Significant Accounting Policies - Additional Information (Details)			12 Months Ended
	Feb. 07, 2020	Jan. 01, 2020 USD ($)	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Reverse stock split	0.2055
Reverse stock split, description	1-for-4.8661
Other-than-temporary impairment			$ 0
Restricted cash			1,084,000	$ 214,000
Impairments of long-lived assets			0	0	$ 0
Impairment of intangible assets, indefinite-lived			0
Impairment of intangible assets, finite-lived			0
Goodwill impairment			0
Redeemable convertible preferred stock tranche liability							$ 200,000
Redeemable convertible preferred stock tranche obligation						$ 2,100,000
Deferred offering costs			$ 0	2,100,000
Number of operating segment \| Segment			1
Number of reportable segment \| Segment			1
Retirement plan name description			401(k) retirement plan
Retirement plan, matching contributions			$ 200,000	200,000	$ 0
Operating lease liability			32,664,000
Operating lease right-of-use asset			27,435,000
Accumulated deficit			$ (265,545,000)	(157,386,000)
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date			Jan. 01, 2020
Change in accounting principle, accounting standards update, early adoption			false
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, immaterial effect			true
Operating lease liability		$ 11,500,000
Operating lease right-of-use asset		9,100,000
Deferred rent derecognized		$ 2,400,000
Estimated incremental borrowing rate of funds		5.00%
ASU 2016-02 \| Cumulative Effect Period of Adoption Adjustment
Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit		$ 0
ASU 2018-11
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date			Jan. 01, 2020
Change in accounting principle, accounting standards update, early adoption			false
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, immaterial effect			true
ASU 2019-01
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date			Jan. 01, 2020
Change in accounting principle, accounting standards update, early adoption			false
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, immaterial effect			true
ASU 2018-07
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date			Jan. 01, 2020
Change in accounting principle, accounting standards update, early adoption			false
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, immaterial effect			true
ASU 2018-13
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date			Jan. 01, 2020
Change in accounting principle, accounting standards update, early adoption			false
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, immaterial effect			true
ASU 2018-18
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date			Jan. 01, 2020
Change in accounting principle, accounting standards update, early adoption			false
Change in accounting principle, accounting standards update, adopted			true
Change in accounting principle, accounting standards update, immaterial effect			true
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives			3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives			5 years
Letter Of Credit
Summary Of Significant Accounting Policies [Line Items]
Restricted cash			$ 1,100,000	$ 200,000

Summary of Significant Accounting Policies - Schedule of Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2020
Minimum
Property Plant And Equipment [Line Items]
Estimated useful life	3 years
Maximum
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Laboratory Equipment \| Minimum
Property Plant And Equipment [Line Items]
Estimated useful life	4 years
Laboratory Equipment \| Maximum
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Estimated useful life, description	Lesser of estimated useful life or remaining lease term
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Estimated useful life	3 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Estimated useful life	5 years

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	$ 442,079	$ 123,617
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	16,696	9,369
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	151,663	32,597
U.s. Government And Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	270,520	42,814
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	3,200	38,837
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	16,696	9,369
Level 1 \| Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	16,696	9,369
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	425,383	114,248
Level 2 \| Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	151,663	32,597
Level 2 \| U.s. Government And Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	270,520	42,814
Level 2 \| Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	$ 3,200	$ 38,837

Fair Value Measurements - Additional Information (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair value, transfers between Levels 1, 2 or 3, amount	$ 0	$ 0

Available-for-sale Securities - Summary of Estimated Value of Available-for-sale Securities and Cash Equivalents and Gross Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 441,963	$ 123,543
Gross Unrealized Gain	131	79
Gross Unrealized Loss	(15)	(5)
Estimated Fair Value	442,079	123,617
Marketable Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	336,352	106,025
Gross Unrealized Gain	131	79
Gross Unrealized Loss	(10)	(5)
Estimated Fair Value	336,473	106,099
Marketable Securities \| Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		38,802
Gross Unrealized Gain		37
Gross Unrealized Loss		(2)
Estimated Fair Value		38,837
Marketable Securities \| Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	69,871	24,446
Gross Unrealized Gain		3
Gross Unrealized Loss	(5)	(1)
Estimated Fair Value	69,866	24,448
Marketable Securities \| U.S. Government and Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	266,481	42,777
Gross Unrealized Gain	131	39
Gross Unrealized Loss	(5)	(2)
Estimated Fair Value	266,607	42,814
Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	105,611	17,518
Gross Unrealized Loss	(5)
Estimated Fair Value	105,606	17,518
Cash Equivalents \| Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,202
Gross Unrealized Loss	(2)
Estimated Fair Value	3,200
Cash Equivalents \| Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	81,800	8,149
Gross Unrealized Loss	(3)
Estimated Fair Value	81,797	8,149
Cash Equivalents \| U.S. Government and Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,913
Estimated Fair Value	3,913
Cash Equivalents \| Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	16,696	9,369
Estimated Fair Value	$ 16,696	$ 9,369

Available-for-sale Securities - Summary of Amortized Cost and Estimated Fair Value of Available-for-sale Securities and Cash Equivalents by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 441,963	$ 123,543
Gross Unrealized Gain	131	79
Gross Unrealized Loss	(15)	(5)
Estimated Fair Value	442,079	$ 123,617
Mature in One Year or Less
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	409,968
Gross Unrealized Gain	127
Gross Unrealized Loss	(15)
Estimated Fair Value	410,080
Mature after One Year through Two Years
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	31,995
Gross Unrealized Gain	4
Estimated Fair Value	$ 31,999

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 16,972	$ 12,706
Less: accumulated depreciation and amortization	(8,070)	(5,559)
Property and equipment, net	8,902	7,147
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	9,978	8,032
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,387	3,342
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,578	1,284
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	48	$ 48
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,981

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Depreciation and amortization expense	$ 2.6	$ 2.3	$ 1.6

Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Expenses And Other Current Liabilities [Abstract]
Accrued compensation	$ 7,736	$ 4,069
Accrued research and development	10,459	7,195
Deferred rent, current		609
Accrued professional services	492	1,607
Other	97	1,048
Total accrued expenses and other current liabilities	$ 18,784	$ 14,528

Acquisition of Warp Drive - Additional Information (Details) $ / shares in Units, $ in Thousands	1 Months Ended	2 Months Ended	12 Months Ended
	Oct. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($)	Nov. 30, 2018 $ / shares	Jun. 30, 2018 $ / shares
Business Acquisition [Line Items]
Useful life of intangible assets			4 years 9 months 18 days	5 years 9 months 18 days
Amortization expenses			$ 1,068	$ 1,069	$ 198
Cash consideration				6,000
Loss on disposal of held-for-sale assets				(597)
Goodwill			$ 14,608	14,608
Severance costs					1,400
Gingko Bioworks
Business Acquisition [Line Items]
Cash consideration				$ 6,000
Percentage of future milestones payments receivable				25.00%
General and Administrative Expenses \| Gingko Bioworks
Business Acquisition [Line Items]
Loss on disposal of held-for-sale assets				$ 600
Series B Redeemable Convertible Preferred Stock
Business Acquisition [Line Items]
Redeemable convertible preferred stock, issued price per share \| $ / shares				$ 7.30		$ 10.03	$ 7.30
Warp Drive
Business Acquisition [Line Items]
Business acquisition, other consideration	$ 900
Business acquisition, total consideration	69,006
Cash consideration	1,172
Contingently returnable consideration asset	310
Transaction costs	600
Goodwill	14,608
Revenue of acquiree since acquisition date		$ 700
Net loss of acquiree since acquisition date		$ 4,200
Warp Drive \| Developed Technology - Tri-complex Platform
Business Acquisition [Line Items]
Useful life of intangible assets			7 years
Amortization expenses			$ 1,100	$ 1,100	200
Warp Drive \| In-process Research and Development - RAS Programs
Business Acquisition [Line Items]
In-process research and development - RAS programs	55,800
Warp Drive \| In-process Research and Development - KRASG12C Program
Business Acquisition [Line Items]
In-process research and development - RAS programs	44,100
Warp Drive \| In-process Research and Development - KRASG12D Program
Business Acquisition [Line Items]
In-process research and development - RAS programs	$ 11,700
Warp Drive \| Income Approach \| Discount Rates \| Developed Technology - Genome Mining Platform
Business Acquisition [Line Items]
Intangible assets, measurement input			0.14
Warp Drive \| Income Approach \| Discount Rates \| In-process Research and Development - RAS Programs
Business Acquisition [Line Items]
Intangible assets, measurement input			0.13
Warp Drive \| General and Administrative Expenses
Business Acquisition [Line Items]
Acquisition-related costs					$ 400
Warp Drive \| Series B Redeemable Convertible Preferred Stock
Business Acquisition [Line Items]
Business acquisition, shares issued \| shares	6,797,915
Redeemable convertible preferred stock, issued price per share \| $ / shares	$ 10.03
Holdback Provision Associated with Warp Drive’s Agreement with Roche
Business Acquisition [Line Items]
Contingently returnable consideration asset	$ 300
Holdback Provision Associated with Warp Drive’s Agreement with Roche \| Maximum
Business Acquisition [Line Items]
Cash consideration	$ 100
Holdback Provision Associated with Warp Drive’s Agreement with Roche \| Series B Redeemable Convertible Preferred Stock
Business Acquisition [Line Items]
Business acquisition, shares issued \| shares	494,771

Acquisition of Warp Drive - Summary of Purchase Price Consideration For Acquisition (Details) - Warp Drive $ in Thousands	1 Months Ended
	Oct. 31, 2018 USD ($)
Business Acquisition [Line Items]
Cash	$ 1,172
Contingently returnable consideration asset	(310)
Total consideration	69,006
Series B Redeemable Convertible Preferred Stock
Business Acquisition [Line Items]
Series B redeemable convertible preferred stock	$ 68,144

Acquisition of Warp Drive - Summary of Fair Values of Assets Acquired and Liabilities Assumed at Acquisition Date (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Oct. 31, 2018
Liabilities assumed:
Goodwill	$ 14,608	$ 14,608
Warp Drive
Assets acquired:
Cash and other current assets			$ 1,594
Property and equipment			2,151
Total assets acquired			73,125
Liabilities assumed:
Accounts payable and other accrued liabilities			3,790
Convertible note payable, related party			2,000
Deferred revenue			745
Deferred tax liability			12,192
Total liabilities assumed			18,727
Goodwill			14,608
Total			69,006
Warp Drive \| In-process Research and Development - RAS Programs
Assets acquired:
In-process research and development - RAS programs			55,800
Warp Drive \| Developed Technology - Tri-complex Platform
Assets acquired:
Developed technology			7,480
Warp Drive \| Developed Technology - Genome Mining Platform
Assets acquired:
Developed technology			$ 6,100

Acquisition of Warp Drive - Summary of Proforma Financial Information of Acquisition (Details) - Warp Drive $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Revenue	$ 20,302
Net loss	$ (57,151)

Intangible Assets and Goodwill - Schedule of Intangibles Assets, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
In-process research and development-RAS Programs	$ 55,800	$ 55,800
Developed technology - tri-complex platform, Gross value	7,480	7,480
Developed technology - tri-complex platform, Accumulated amortization	(2,335)	(1,267)
Developed technology - tri-complex platform, Net book value	$ 5,145	$ 6,213
Developed technology - tri-complex platform, Weighted-average remaining useful life	4 years 9 months 18 days	5 years 9 months 18 days
Intangible assets, Gross value	$ 63,280	$ 63,280
Intangible assets, Net book value	$ 60,945	$ 62,013

Intangible Assets and Goodwill - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 1,068,000	$ 1,069,000	$ 198,000
Goodwill impairment	$ 0

Intangible Assets and Goodwill - Schedule of Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2021	$ 1,069
2022	1,069
2023	1,069
2024	1,069
2025	869
Developed technology - tri-complex platform, Net book value	$ 5,145	$ 6,213

Intangible Assets and Goodwill - Schedule of Goodwill (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Balance at December 31, 2019	$ 14,608
Balance at December 31, 2020	$ 14,608

Commitment and Contingencies - Additional Information (Details)	1 Months Ended	12 Months Ended
	Apr. 30, 2020 USD ($) ft²	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jan. 01, 2020 USD ($)	Oct. 31, 2018 ft²	Jan. 31, 2015 ft²
Lessee Lease Description [Line Items]
Operating lease right-of-use asset		$ 27,435,000
Operating lease liability		32,664,000
Increase in operating lease liability		(2,565,000)
Sublease income		1,900,000
Operating lease cost		2,700,000
Tenant improvement allowance credits		200,000
Operating cash flows for operating leases		$ 2,600,000
Operating lease, weighted average discount rate		7.10%
Operating lease, weighted average remaining lease term		9 years 1 month 6 days
Capital lease obligations		$ 200,000
Rent expense			$ 2,000,000	$ 1,500,000
Deferred rent		2,400,000
ASC 842
Lessee Lease Description [Line Items]
Operating lease right-of-use asset					$ 9,100,000
Operating lease liability					$ 11,500,000
Redwood City Lease
Lessee Lease Description [Line Items]
Sublease income		0	0	900,000
Redwood City Lease \| Other Noncurrent Assets
Lessee Lease Description [Line Items]
Security deposit			300,000	$ 300,000
Redwood City Lease \| Restricted Cash
Lessee Lease Description [Line Items]
Letter of credit		$ 900,000
Redwood City Lease \| The 700 Building
Lessee Lease Description [Line Items]
Lessee operating lease expiration month and year		2023-04
Area of space leased \| ft²							42,000
Lease expiration date	Dec. 31, 2030
Lessee, operating lease, option to extend		Option to extend the lease term for the 700 Building and the 300 Building together for an additional ten years after December 31, 2030
Lessee, operating lease option to extend lease term	10 years
Percentage of increase in annual base rent	3.50%
Operating lease, rent description	The annual base rent for the lease of the 700 Building remains unchanged through April 30, 2023, and increases to $2.8 million for the 12 month period ending April 30, 2024, after which the annual base rent increases by approximately 3.5% in each subsequent year of the lease term.
Tenant improvement allowance		$ 3,400,000
Redwood City Lease \| The 700 Building \| ASC 842
Lessee Lease Description [Line Items]
Operating lease right-of-use asset		6,400,000
Operating lease liability		$ 9,000,000
Redwood City Lease \| The 700 Building \| Lease Term Until April 30, 2023
Lessee Lease Description [Line Items]
Annual base rent for lease	$ 2,800,000
Redwood City Lease \| Three Hundred Saginaw Drive Redwood City California
Lessee Lease Description [Line Items]
Area of space leased \| ft²	19,000
Lease beginning date	Dec. 15, 2020
Lease expiration date	Dec. 31, 2030
Lessee, operating lease, option to extend		Option to extend the lease term for the 700 Building and the 300 Building together for an additional ten years after December 31, 2030
Lessee, operating lease option to extend lease term	10 years
Percentage of increase in annual base rent	3.50%
Operating lease, rent description	The annual base rent for the lease of the 300 Building is $1.2 million until December 31, 2021, after which the annual base rent will increase by approximately 3.5% in each subsequent year of the lease term.
Tenant improvement allowance		$ 3,200,000
Redwood City Lease \| Three Hundred Saginaw Drive Redwood City California \| ASC 842
Lessee Lease Description [Line Items]
Increase in operating lease right-of-use asset		14,800,000
Increase in operating lease liability		$ 14,800,000
Redwood City Lease \| Three Hundred Saginaw Drive Redwood City California \| Lease Term Expiring Until December 31, 2021
Lessee Lease Description [Line Items]
Annual base rent for lease	$ 1,200,000
Cambridge, Massachusetts
Lessee Lease Description [Line Items]
Lessee operating lease expiration month and year		2023-02
Area of space leased \| ft²						22,000
Lessee, operating lease, option to extend		Option to extend the term through February 2028
Cambridge, Massachusetts \| Restricted Cash
Lessee Lease Description [Line Items]
Letter of credit		$ 200,000	$ 200,000

Commitment and Contingencies - Summary of Balance Sheet Classification of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating lease liability – current	$ 3,672
Operating lease liability – noncurrent	28,992
Total operating lease liabilities	32,664
Accrued expenses and other current liabilities	$ 19
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	rvmd:AccruedResearchAndDevelopmentExpensesCurrent
Total financing lease liabilities	$ 19
Total lease liabilities	$ 32,683

Commitment and Contingencies - Schedule of Maturities of Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2021	$ 4,381
2022	5,144
2023	4,173
2024	4,215
2025	4,363
Thereafter	24,213
Total undiscounted lease payments	46,489
Less: Imputed interest	(10,669)
Less: Tenant improvement allowance	(3,156)
Total operating lease liabilities	$ 32,664

Commitment and Contingencies - Schedule of Future Minimum Payment and Receipts Under Operating and Capital Lease and Sublease (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Gross lease commitments 2020	$ 3,885
Gross lease commitments 2021	3,786
Gross lease commitments 2022	3,886
Gross lease commitments 2023	1,003
Total Gross lease commitments	12,560
Sublease income 2020	(1,701)
Sublease income 2021	(1,752)
Sublease income 2022	(1,804)
Sublease income 2023	(302)
Total Sublease income	(5,559)
2020	2,184
2021	2,034
2022	2,082
2023	701
Total future minimum lease payments	$ 7,001

Sanofi Collaboration Agreement - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 31, 2018
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue, related party, current	$ 12,111,000	$ 17,124,000
Deferred revenue, related party, noncurrent	8,481,000	$ 14,727,000
Sanofi Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront cash payment received	$ 50,000,000			$ 50,000,000
Maximum development and regulatory milestone payments to be received				520,000,000
Maximum milestone payments receivable upon achievement of specified development milestones				235,000,000
Maximum milestone payments receivable upon achievement of certain marketing approval milestones				$ 285,000,000
Percentage of reimbursement of internal and external research costs and expenses under research plan	80.00%	80.00%
Percentage of other internal and external costs and expenses incurred under research and development plans	20.00%	20.00%
Transaction price	$ 196,100,000
Estimated variable consideration for expense reimbursements upon research and development services	146,100,000
Collaboration revenue recognized	43,000,000	$ 50,000,000	$ 19,400,000
Deferred revenue, related party, current	12,100,000	17,100,000
Deferred revenue, related party, noncurrent	$ 8,500,000	$ 14,700,000

Redeemable Convertible Preferred Stock - Additional Information (Details) - USD ($)			1 Months Ended		2 Months Ended	4 Months Ended	12 Months Ended			30 Months Ended
	Feb. 18, 2020	Oct. 30, 2018	Nov. 30, 2018	Oct. 31, 2018	Jul. 31, 2019	Jun. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2017	Feb. 29, 2020
Temporary Equity [Line Items]
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs								$ 100,028,000	$ 60,558,000
Temporary equity, shares outstanding							0	39,600,423
Gross cash proceeds from issuance of common stock							$ 420,067,000
Dividends declared							0
Dividends paid							$ 0
Stock voting rights description							Each share of redeemable convertible preferred stock had a number of votes equal to the number of shares of common stock into which it was convertible. The holders of Series A redeemable convertible preferred stock had the right to elect two members of the Company’s Board of Directors. The holders of Series B redeemable convertible preferred stock had the right to elect one member of the Company’s Board of Directors. The holders of common stock had the right to elect one member of the Company’s Board of Directors. The holders of common stock and redeemable convertible preferred stock, voting together as a single class on an as-converted basis, were entitled to elect one member of the Board of Directors.
Common Stock
Temporary Equity [Line Items]
Conversion of shares							39,600,423
Initial Public Offering
Temporary Equity [Line Items]
Temporary equity, shares outstanding											39,600,423
Gross cash proceeds from issuance of common stock	$ 250,700,000
Stock issued, price per share	$ 17.00
Initial Public Offering \| Common Stock \| Minimum
Temporary Equity [Line Items]
Gross cash proceeds from issuance of common stock							$ 50,000,000
Stock issued, price per share							$ 10.03
Warp Drive
Temporary Equity [Line Items]
Convertible notes payable				$ 2,000,000
Series A Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued										14,430,799
Redeemable convertible preferred stock, issued price per share								$ 4.87		$ 4.87
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs										$ 70,100,000
Temporary equity, shares outstanding								14,430,799
Cumulative cash dividend rate							6.00%
Series B Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued			435,547			7,731,155
Redeemable convertible preferred stock, issued price per share			$ 10.03			$ 7.30		$ 7.30
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs			$ 4,300,000			$ 56,200,000
Temporary equity, shares outstanding								15,165,110
Cumulative cash dividend rate							6.00%
Series B Redeemable Convertible Preferred Stock \| Warp Drive
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued				6,797,915
Redeemable convertible preferred stock, issued price per share				$ 10.03
Convertible notes payable				$ 2,000,000
Conversion of shares		200,493		200,493
Series C Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued					10,004,514
Redeemable convertible preferred stock, issued price per share					$ 10.03			$ 10.03
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs					$ 100,000,000
Temporary equity, shares outstanding								10,004,514
Cumulative cash dividend rate							6.00%

Redeemable Convertible Preferred Stock - Schedule of Redeemable Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Shares Authorized	0	192,904,770
Shares issued	0	39,600,423
Shares outstanding	0	39,600,423
Net carrying value		$ 305,109
Aggregate liquidation preference	$ 0	$ 308,688
Series A
Temporary Equity [Line Items]
Shares Authorized		70,221,732
Shares issued		14,430,799
Shares outstanding		14,430,799
Net carrying value		$ 72,248
Aggregate liquidation preference		$ 84,865
Series B
Temporary Equity [Line Items]
Shares Authorized		74,000,000
Shares issued		15,165,110
Shares outstanding		15,165,110
Net carrying value		$ 132,833
Aggregate liquidation preference		$ 120,152
Series C
Temporary Equity [Line Items]
Shares Authorized		48,683,038
Shares issued		10,004,514
Shares outstanding		10,004,514
Net carrying value		$ 100,028
Aggregate liquidation preference		$ 103,671

Common Stock - Additional Information (Details)	12 Months Ended
Common Stock - Additional Information (Details)	Dec. 31, 2020 USD ($) Vote $ / shares shares	Dec. 31, 2019 $ / shares shares
Stockholders Equity Note [Abstract]
Common stock, shares authorized \| shares	300,000,000	249,000,000
Common stock, par or stated value per share \| $ / shares	$ 0.0001	$ 0.0001
Common stock, voting rights	Each share of common stock is entitled to one vote
Number of voting rights per common share \| Vote	1
Common stock, dividends declared \| $	$ 0

Common Stock - Schedule of Common Stock Reserved on Converted Basis for Future Issuance (Details) - shares	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common stock reserved for future issuance, Total	10,511,256	45,322,374
Redeemable Convertible Preferred Stock
Class Of Stock [Line Items]
Common stock reserved for future issuance, Total		39,600,423
Outstanding Options to Purchase Common Stock
Class Of Stock [Line Items]
Common stock reserved for future issuance, Total	5,118,979	4,918,299
Unvested Restricted Stock Units Of Common Stock
Class Of Stock [Line Items]
Common stock reserved for future issuance, Total	85,639
Available for Future Issuance under the 2020 Incentive Award Plan
Class Of Stock [Line Items]
Common stock reserved for future issuance, Total	4,806,916
Available for issuance under the 2020 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Common stock reserved for future issuance, Total	499,722
Available for future issuance under the 2014 Equity Incentive Plan
Class Of Stock [Line Items]
Common stock reserved for future issuance, Total		803,652

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	12 Months Ended
	Feb. 29, 2020	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance, Total				10,511,256	45,322,374
Shares subject to repurchase				130,793	349,501
Exercise price of early exercised shares				$ 200	$ 300
Intrinsic value of the options exercised				$ 21,700	$ 400	$ 400
Weighted-average grant-date fair value of options granted				$ 15.59	$ 4.43	$ 1.90
Unrecognized stock-based compensation expense related to unvested stock options				$ 22,100
Unrecognized stock-based compensation expense, weighted-average period of recognition				2 years 6 months
Stock-based compensation expense				$ 8,886	$ 3,161	$ 855
Non-employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense				$ 800	700	300
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense, weighted-average period of recognition				3 years 3 months 18 days
Unrecognized compensation cost				$ 2,700
RSU vested, fair value				$ 100	$ 0	$ 0
2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	4 years
Common stock reserved for future issuance, Total				4,806,916
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
2014 Equity Incentive Plan \| Restricted Stock Awards \| Employee And Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period			4 years
Share Price			$ 0.0001
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance, Total	528,959			499,722
Purchase price rate	85.00%
Shares purchases				29,237
Unrecognized compensation cost related to ESPP				$ 1,500

Stock-Based Compensation - Summary of Option Activity Under the Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options exercised	$ (21,700)	$ (400)	$ (400)
2020 Plan and 2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares underlying options, Beginning balance	4,918,299	1,632,797
Number of Shares underlying options, Options granted	967,874	3,516,276
Number of Shares underlying options, Options exercised	(694,441)	(171,110)
Number of Shares underlying options, Options cancelled	(72,753)	(59,664)
Number of Shares underlying options, Ending balance	5,118,979	4,918,299	1,632,797
Number of Shares underlying options, Options vested and expected to vest	5,118,979
Number of Shares underlying options, Options vested and exercisable	1,966,195
Weighted-average exercise price, Beginning balance	$ 3.59	$ 0.98
Weighted-average exercise price, Options granted	23.33	4.73
Weighted-average exercise price, Options exercised	2.77	2.01
Weighted-average exercise price, Options cancelled	8.16	3.73
Weighted-average exercise price, Ending balance	7.37	$ 3.59	$ 0.98
Weighted-average exercise price, Options vested and expected to vest	7.37
Weighted-average exercise price, Options vested and exercisable	$ 4.08
Weighted-average remaining contractual term (in years)	8 years 3 months	8 years 11 months 15 days	8 years 9 months 3 days
Weighted-average exercise price, Options vested and expected to vest	8 years 3 months
Weighted-average exercise price, Options vested and exercisable	7 years 9 months
Aggregate intrinsic value	$ 165,088	$ 51,276	$ 5,085
Aggregate intrinsic value, Options vested and expected to vest	165,088
Aggregate intrinsic value, Options vested and exercisable	$ 69,825

Summary of Fair Value of Stock Option Awards Estimated at Date of Grant (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee And Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	6 years
Expected volatility, minimum	74.00%	76.00%	79.00%
Expected volatility, maximum	80.00%	82.00%	81.00%
Risk-free interest rate, minimum	0.20%	1.60%	2.50%
Risk-free interest rate, maximum	1.50%	2.50%	3.00%
Dividend yield	0.00%	0.00%	0.00%
Employee And Director \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)		5 years	5 years
Employee And Director \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)		6 years	6 years
Non-employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	74.00%	79.00%
Expected volatility, maximum	80.00%	83.00%
Risk-free interest rate, minimum	1.20%	1.60%	2.90%
Risk-free interest rate, maximum	1.50%	2.60%	3.00%
Dividend yield	0.00%	0.00%	0.00%
Expected volatility			80.00%
Non-employee \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	6 years	6 years	7 years
Non-employee \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	10 years	10 years	10 years

Stock-Based Compensation - Summary of RSUs Activity Under the Plan (Details) - 2020 Equity Incentive Plan - Restricted Stock Units (RSUs) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Restricted stock units granted \| shares	87,520
Number of Shares, Restricted stock units vested \| shares	(1,681)
Number of Shares, Restricted stock units forfeited \| shares	(200)
Number of Shares, Ending balance \| shares	85,639
Number of Shares, Expected to vest \| shares	85,639
Weighted-average grant date fair value per share, Restricted stock units granted \| $ / shares	$ 35.12
Weighted-average grant date fair value per share, Restricted stock units vested \| $ / shares	34.98
Weighted-average grant date fair value per share, Restricted stock units forfeited \| $ / shares	30.96
Weighted-average grant date fair value per share, Ending balance \| $ / shares	35.13
Weighted-average grant date fair value per share, Expected to vest \| $ / shares	$ 35.13
Weighted-average remaining contractual term (in years)	1 year 8 months 23 days
Weighted-average remaining contractual term, Expected to vest	1 year 8 months 23 days
Aggregate intrinsic value \| $	$ 3,390
Aggregate intrinsic value, Expected to vest \| $	$ 3,390

Stock-Based Compensation - Summary of Total Stock-Based Compensation Expense Related to Stock Options, RSUs and Employee Stock Purchase Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 8,886	$ 3,161	$ 855
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	4,848	1,789	563
General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,038	$ 1,372	$ 292

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Line Items]
Benefit from income taxes	$ 371,000	$ 4,373,000
Increase in valuation allowance	$ 37,300,000	12,600,000
Tax cut and jobs act net operating loss deduction limitation percentage	80.00%
Research and development credit carryforwards	$ 10,346,000	6,764,000
Net operating losses, limitations on use	Federal, California, Massachusetts and New Jersey tax laws impose significant restrictions on the utilization of net operating loss carryforwards in the event of a change in ownership of the Company, as defined by Internal Revenue Code Section 382 (Section 382). The Company performed a study in which it determined that it had experienced changes in ownership in December 2014, June 2018, and March 2020 as defined by Section 382. No federal or state net operating losses are expected to expire unutilized as a result of the limitation, with the exception of $5.5 million in California net operating losses. In addition, in the future the Company may experience ownership changes, which may limit the utilization of net operating loss carryforwards or other tax attributes.
Unrecognized tax benefits that would affect effective tax rate if recognized	$ 3,300,000	2,200,000
Interest or penalties related to uncertain tax positions	$ 0	$ 0
Years remain open to examination	2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
Massachusetts
Income Taxes [Line Items]
Net operating loss carryforwards subject to expire	$ 55,000,000
Net operating loss carryforwards expiration beginning year	2035
New Jersey
Income Taxes [Line Items]
Net operating loss carryforwards subject to expire	$ 163,400,000
Net operating loss carryforwards expiration beginning year	2039
Federal
Income Taxes [Line Items]
Net operating loss carryforwards subject to expire	$ 265,800,000
Net operating loss carryforwards expiration beginning year	2035
Net operating loss carryforwards which can be carried forward indefinitely	$ 172,100,000
Research and development credit carryforwards	$ 9,000,000
Research and development credit carryforwards expiration starting year	2034
California State
Income Taxes [Line Items]
Net operating loss carryforwards subject to expire	$ 52,700,000
Net operating loss carryforwards expiration beginning year	2035
Research and development credit carryforwards	$ 5,800,000
Research and development credit carryforwards expiration starting year	2031
Research and development credit carryforwards which can be carried forward indefinitely	$ 5,000,000
Net operating losses expected to expire unutilized as a result of the limitation	$ 5,500,000

Income Taxes - Summary of Benefit from Income Taxes to Amount Computed by Applying Federal Statutory Rate to Loss Before Taxes (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]
Federal statutory income tax rate	21.00%	21.00%
State income tax rate, net of federal benefit	9.70%	10.70%
Research tax credits	3.30%	1.00%
Change in valuation allowance	(34.30%)	(24.20%)
Non-deductible permanent expenses	0.90%	(0.50%)
Other	(0.30%)	0.40%
Benefit from income taxes	0.30%	8.40%

Income Taxes - Summary of Categories that Give Rise to Significant Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 74,137	$ 38,511
Accruals and reserves	8,505	11,927
Research and development credits	10,346	6,764
Lease liability	9,845
Stock-based compensation	1,241	1,021
Other	38	38
Gross deferred tax assets	104,112	58,261
Less: valuation allowance	(84,680)	(47,426)
Total deferred tax assets	19,432	10,835
Deferred tax liabilities:
Fixed assets and finite-lived intangible assets	(10,397)	(10,836)
Indefinite-lived intangible assets	(7,444)	(7,818)
Lease asset	(766)
Right-of-use asset	(8,269)
Gross deferred tax liabilities	(26,876)	(18,654)
Net deferred tax liability	$ (7,444)	$ (7,819)

Income Taxes - Reconciliation of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Beginning balance	$ 2,419	$ 2,441
Changes related to tax positions taken in the prior year	(41)	(567)
Changes related to tax positions taken in current year	1,215	545
Ending balance	$ 3,593	$ 2,419

Net Loss Per Share Attributable to Common Stockholders - Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss	$ (34,204)	$ (27,221)	$ (27,215)	$ (19,519)	$ (14,596)	$ (12,818)	$ (10,119)	$ (10,131)	$ (108,159)	$ (47,664)	$ (41,789)
Redeemable convertible preferred stock dividends - undeclared and cumulative									(2,219)	(14,238)	(7,031)
Net loss attributable to common stockholders									$ (110,378)	$ (61,902)	$ (48,820)
Denominator:
Weighted-average shares outstanding									55,109,929	3,231,389	3,140,848
Less: Weighted-average unvested restricted shares and shares subject to repurchase									(235,810)	(458,800)	(842,028)
Weighted-average shares used to compute net loss per share attributable to common stockholders-basic and diluted									54,874,119	2,772,589	2,298,820
Net loss per share attributable to common stockholders - basic and diluted	$ (0.52)	$ (0.42)	$ (0.46)	$ (0.74)	$ (6.48)	$ (6.08)	$ (4.85)	$ (4.84)	$ (2.01)	$ (22.33)	$ (21.24)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

+ References

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+ Details

Net Loss Per Share Attributable to Common Stockholders - Schedule of Outstanding Potentially Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive shares	5,426,621	44,868,223	31,844,448
Redeemable Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive shares		39,600,423	29,595,909
Option to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive shares	5,118,979	4,918,299	1,632,797
Options Early Exercised Subject to Future Vesting
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive shares	130,793	349,501	615,742
Unvested Restricted Stock Units Of Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive shares	85,639
Expected Shares To Be Purchased Under ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive shares	91,210

Related Party Relationships - Additional Information (Details) - USD ($) $ in Millions		1 Months Ended		4 Months Ended
	Oct. 30, 2018	Nov. 30, 2018	Oct. 31, 2018	Jun. 30, 2018
Warp Drive
Related Party Transaction [Line Items]
Convertible notes payable			$ 2.0
Convertible note annual interest rate computed on basis of a 360-day year			8.00%
Series B Redeemable Convertible Preferred Stock
Related Party Transaction [Line Items]
Issuance of redeemable convertible preferred stock, net of issuance costs, shares		435,547		7,731,155
Series B Redeemable Convertible Preferred Stock \| Warp Drive
Related Party Transaction [Line Items]
Issuance of redeemable convertible preferred stock, net of issuance costs, shares			6,797,915
Convertible notes payable			$ 2.0
Conversion of redeemable convertible preferred stock into common stock, shares	200,493		200,493
Series B Redeemable Convertible Preferred Stock \| Third Rock Ventures
Related Party Transaction [Line Items]
Issuance of redeemable convertible preferred stock, net of issuance costs, shares			1,708,824
Sanofi Agreement \| Series B Redeemable Convertible Preferred Stock
Related Party Transaction [Line Items]
Issuance of redeemable convertible preferred stock, net of issuance costs, shares			3,363,050

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Feb. 28, 2021	Jul. 31, 2020	Dec. 31, 2020	Feb. 18, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common stock, shares, issued			66,599,748		3,292,124
Net proceeds from issuance			$ 420,067
Underwritten Public Offering
Class Of Stock [Line Items]
Common stock, shares, issued		6,900,000
Common stock, price per share		$ 26.00
Net proceeds from issuance		$ 167,800
Underwritten Public Offering \| Subsequent Event
Class Of Stock [Line Items]
Common stock, shares, issued	6,666,666
Common stock, price per share	$ 45.00
Net proceeds from issuance	$ 281,300
Underwriter's Option to Purchase Additional Shares
Class Of Stock [Line Items]
Common stock, shares, issued		900,000		2,100,000
Underwriter's Option to Purchase Additional Shares \| Subsequent Event
Class Of Stock [Line Items]
Common stock, shares, issued	869,565

Selected Quarterly Financial Data (Unaudited) - Summary of Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Revenue	$ 8,751	$ 12,661	$ 10,025	$ 11,546	$ 12,088	$ 12,506	$ 12,281	$ 13,166	$ 42,983	$ 50,041	$ 20,165
Net loss	$ (34,204)	$ (27,221)	$ (27,215)	$ (19,519)	$ (14,596)	$ (12,818)	$ (10,119)	$ (10,131)	$ (108,159)	$ (47,664)	$ (41,789)
Net loss per share attributable to common stockholders - basic and diluted	$ (0.52)	$ (0.42)	$ (0.46)	$ (0.74)	$ (6.48)	$ (6.08)	$ (4.85)	$ (4.84)	$ (2.01)	$ (22.33)	$ (21.24)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
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+ Details