IDEAYA Biosciences (IDYA) 10-K 17 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 14, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Trading Symbol	IDYA
Entity Registrant Name	IDEAYA Biosciences, Inc.
Entity Central Index Key	0001676725
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
ICFR Auditor Attestation Flag	false
Entity Common Stock, Shares Outstanding		38,627,222
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity File Number	001-38915
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-4268251
Entity Address, Address Line One	7000 Shoreline Court
Entity Address, Address Line Two	Suite 350
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	443-6209
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 629.1
Document Annual Report	true
Document Transition Report	false
Auditor Firm ID	238
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	San Jose, California
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive Proxy Statement relating to the 2022 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, 2021.

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 92,046	$ 72,037
Short-term marketable securities	154,724	211,548
Accounts receivable	1,103	1,877
Prepaid expenses and other current assets	3,123	3,143
Total current assets	250,996	288,605
Restricted cash	106	106
Long-term marketable securities	121,293	0
Property and equipment, net	4,763	4,271
Right-of-use assets	3,898	5,205
Other non-current assets	291	82
Total assets	381,347	298,269
Current liabilities
Accounts payable	2,100	953
Accrued liabilities	12,320	8,516
Contract liability	29,040	27,613
Operating lease liabilities, current	1,699	1,540
Other current liabilities		18
Total current liabilities	45,159	38,640
Long-term contract liability	31,192	56,160
Long-term operating lease liabilities	3,482	5,183
Other non-current liabilities		12
Total liabilities	79,833	99,995
Commitments and contingencies (Note 6)
Stockholders’ equity
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of December 31, 2021 and December 31, 2020; no shares issued and outstanding as of December 31, 2021 and December 31, 2020
Common stock, $0.0001 par value, 300,000,000 shares authorized as of December 31, 2021 and December 31, 2020; 38,533,045 and 29,537,216 shares issued and outstanding as of December 31, 2021 and December 31, 2020	4	3
Additional paid-in capital	478,970	325,250
Accumulated other comprehensive (loss) income	(712)	7
Accumulated deficit	(176,748)	(126,986)
Total stockholders’ equity	301,514	198,274
Total liabilities and stockholders’ equity	$ 381,347	$ 298,269

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	38,533,045	29,537,216
Common stock, shares outstanding	38,533,045	29,537,216

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Collaboration revenue	$ 27,941	$ 19,538	$ 0
Operating expenses
Research and development	58,158	39,698	34,319
General and administrative	20,051	15,184	9,952
Total operating expenses	78,209	54,882	44,271
Loss from operations	(50,268)	(35,344)	(44,271)
Interest income and other income, net	506	849	2,296
Net loss	(49,762)	(34,495)	(41,975)
Unrealized (losses) gains on marketable securities	(719)	(58)	96
Comprehensive loss	$ (50,481)	$ (34,553)	$ (41,879)
Net loss per common share, basic and diluted	$ (1.41)	$ (1.40)	$ (3.36)
Weighted-average number of common shares outstanding used in computing net loss per share, basic and diluted	35,252,443	24,721,775	12,496,957

Statements of Redeemable Conver

Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Follow On Public Offering	Initial Public Offering	At The Market Offering	Private Placement	Redeemable Convertible Preferred Stock	Common Stock	Common StockFollow On Public Offering	Common StockInitial Public Offering	Common StockAt The Market Offering	Common StockPrivate Placement	Additional Paid-In Capital	Additional Paid-In CapitalFollow On Public Offering	Additional Paid-In CapitalInitial Public Offering	Additional Paid-In CapitalAt The Market Offering	Additional Paid-In CapitalPrivate Placement	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2018						$ 138,391
Redeemable convertible preferred stock, beginning balance, shares at Dec. 31, 2018						13,139,794
Conversion of redeemable convertible preferred stock into common stock						$ (138,391)
Conversion of redeemable convertible preferred stock into common stock, shares						(13,139,794)
Beginning balance at Dec. 31, 2018	$ (48,948)											$ 1,599					$ (31)	$ (50,516)
Beginning balance, shares at Dec. 31, 2018							1,335,690
Conversion of redeemable convertible preferred stock into common stock	138,391						$ 1					138,390
Conversion of redeemable convertible preferred stock into common stock, shares							13,139,794
Issuance of common stock, net of issuance cost			$ 50,247						$ 1					$ 50,246
Issuance of common stock, net of issuance costs, shares									5,750,000
Issuance of common stock upon exercise of stock options	307											307
Issuance of common stock upon exercise of stock options, shares							135,563
Early exercised common stock options, shares							2,112
Repurchase of early exercised shares, shares							(23,698)
Vesting of early exercised common stock options and restricted stock	114											114
Stock-based compensation	2,168											2,168
Other comprehensive income (loss)	96																96
Net loss	(41,975)																	(41,975)
Ending balance at Dec. 31, 2019	100,400						$ 2					192,824					65	(92,491)
Ending balance, shares at Dec. 31, 2019							20,339,461
Issuance of common stock, net of issuance cost		$ 100,664		$ 6,582	$ 19,988			$ 1					$ 100,663		$ 6,582	$ 19,988
Issuance of common stock, net of issuance costs, shares								7,166,667		410,896	1,333,333
Issuance of common stock upon exercise of stock options	1,202											1,202
Issuance of common stock upon exercise of stock options, shares							256,583
Employee stock purchase plan (ESPP) purchase	$ 326											326
Employee stock purchase plan (ESPP) purchase, shares							40,794
Repurchase of early exercised shares, shares	(10,518)						(10,518)
Vesting of early exercised common stock options and restricted stock	$ 56											56
Stock-based compensation	3,609											3,609
Other comprehensive income (loss)	(58)																(58)
Net loss	(34,495)																	(34,495)
Ending balance at Dec. 31, 2020	198,274						$ 3					325,250					7	(126,986)
Ending balance, shares at Dec. 31, 2020							29,537,216
Issuance of common stock, net of issuance cost		$ 85,990		$ 57,263				$ 1					$ 85,989		$ 57,263
Issuance of common stock, net of issuance costs, shares								5,333,333		3,407,872
Issuance of common stock upon exercise of stock options	1,510											1,510
Issuance of common stock upon exercise of stock options, shares							211,900
Employee stock purchase plan (ESPP) purchase	$ 697											697
Employee stock purchase plan (ESPP) purchase, shares							50,037
Repurchase of early exercised shares, shares	0
Repurchase of unvested restricted stock							(7,313)
Vesting of early exercised common stock options and restricted stock	$ 24											24
Stock-based compensation	8,237											8,237
Other comprehensive income (loss)	(719)																(719)
Net loss	(49,762)																	(49,762)
Ending balance at Dec. 31, 2021	$ 301,514						$ 4					$ 478,970					$ (712)	$ (176,748)
Ending balance, shares at Dec. 31, 2021							38,533,045

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (49,762)	$ (34,495)	$ (41,975)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities
Depreciation and amortization	1,725	1,381	1,245
Net amortization (accretion) of premiums (discounts) on marketable securities	1,834	578	(473)
Stock-based compensation	8,237	3,609	2,168
Loss on sale of property and equipment	0	2	14
Realized gain on marketable securities	0	(18)	(8)
Changes in assets and liabilities
Accounts receivable	774	(1,877)	0
Prepaid expenses and other assets	(189)	(510)	(1,963)
Right-of-use assets	1,307	(148)	1,093
Accounts payable	1,166	225	(195)
Accrued and other liabilities	4,212	2,992	2,030
Contract liabilities	(23,541)	83,773	0
Lease liabilities	(1,542)	(49)	(1,249)
Net cash provided by (used in) operating activities	(55,779)	55,463	(39,313)
Cash flows from investing activities
Purchases of property and equipment, net	(2,644)	(493)	(1,353)
Purchases of marketable securities	(314,996)	(242,314)	(88,004)
Maturities of marketable securities	243,956	96,564	73,528
Sales of marketable securities	4,018	0	18,094
Net cash (used in) provided by investing activities	(69,666)	(146,243)	2,265
Cash flows from financing activities
Proceeds from issuance of common stock in public offering, net of issuance costs	85,990	100,664	50,321
Proceeds from issuance of common stock in private placement, net of issuance costs	0	19,988	0
Proceeds from issuance of common stock related to at-the-market offering program, net of issuance costs	57,263	6,582	0
Proceeds from exercise of common stock options, net of repurchases	1,504	1,190	289
Proceeds from ESPP purchases	697	326	0
Net cash provided by financing activities	145,454	128,750	50,610
Net increase in cash, cash equivalents and restricted cash	20,009	37,970	13,562
Cash, cash equivalents and restricted cash, at beginning of period	72,143	34,173	20,611
Cash, cash equivalents and restricted cash, at end of period	92,152	72,143	34,173
Reconciliation of cash, cash equivalents and restricted cash
Cash and cash equivalents	92,046	72,037	34,067
Restricted cash	106	106	106
Cash, cash equivalents and restricted cash, at end of period	92,152	72,143	34,173
Supplemental disclosure of cash flow information:
Cash paid for income taxes	4	1	1
Cash paid for interest	71	82	91
Supplemental non-cash investing and financing activities:
Right-of-use asset obtained in exchange for new operating lease liability	0	1,191	0
Vesting of early exercised options and restricted stock	24	56	114
Purchases of property and equipment in accounts payable and accrued liabilities	92	520	0
Conversion of redeemable convertible preferred stock into common stock	$ 0	$ 0	$ 138,391

Organization

Organization	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	1. Organization Description of the Business IDEAYA Biosciences, Inc. (the “Company”) is a synthetic lethality-focused precision medicine oncology company committed to the discovery and development of targeted therapeutics for patient populations selected using molecular diagnostics. The Company is headquartered in South San Francisco, California and was incorporated in the State of Delaware in June 2015. To date, the Company has been primarily engaged in business planning, research, development, recruiting and raising capital. Initial Public Offering On May 22, 2019, the Company’s registration statement on Form S-1 (File No. 333-231081) relating to its initial public offering (“IPO”) of common stock became effective. The IPO closed on May 28, 2019, at which time the Company issued 5,750,000 shares of its common stock at a price of $10.00 per share, which included shares issued upon the underwriters’ exercise of their overallotment option to purchase 750,000 additional shares. In addition, upon closing the IPO, all outstanding shares of the redeemable convertible preferred stock converted into 13,139,794 shares of common stock. The Company received an aggregate of $50.2 million in cash, net of underwriting discounts and commissions of $4.0 million, and after deducting offering costs of $3.3 million. Follow-On Offering On June 22, 2020, the Company completed an underwritten public offering and sold and issued 6,666,667 shares of common stock at a price to the public of $15.00 per share for gross proceeds of $100.0 million. On July 22, 2020, the Company sold and issued an additional 500,000 shares of common stock upon the exercise of the overallotment option by the underwriters for gross proceeds of $7.5 million. The aggregate net proceeds to the Company were $100.7 million after deducting underwriting discounts and commissions and other offering costs. On July 12, 2021, the Company completed an underwritten public offering and sold and issued 5,333,333 shares of common stock, which included shares issued upon the underwriters’ exercise in full of their overallotment option to purchase 695,652 additional shares, at a price to the public of $17.25 per share for net proceeds of $86.0 million, after deducting underwriting discounts and commissions and other offering expenses. Private Placement The Company entered into a stock purchase agreement with Glaxo Group Limited, or GGL, on June 17, 2020, pursuant to which, on August 3, 2020, the Company sold 1,333,333 shares at a price of $15.00 per shares to GGL for net proceeds of $20.0 million in a private placement. At-the-Market Offering On August 12, 2020, the Company filed a prospectus supplement to the prospectus dated June 10, 2020, activating its at-the-market facility by entering into an open market sale agreement (the “August 2020 Sales Agreement) with Jefferies LLC (“Jefferies”), pursuant to which the Company could offer and sell shares of its common stock with an aggregate offering price of up to $50.0 million under an “at the market” offering program. As of January 15, 2021, the Company exhausted all sales under the August 2020 Sales Agreement. On January 20, 2021, the Company entered into a new open market sale agreement (the “January 2021 Sales Agreement”) with Jefferies, pursuant to which the Company may offer and sell shares of its common stock with an aggregate offering price of up to $90.0 million under an “at the market” offering program. For the year ended December 31, 2021, the Company sold an aggregate of 3,407,872 shares for net proceeds of $57.3 million after deducting sales commission and other expenses under the August 2020 Sales Agreement and the January 2021 Sales Agreement. As of December 31, 2021, approximately $73.8 million of common stock remained available to be sold under the January 2021 Sales Agreement. Liquidity The Company has incurred significant losses and negative cash flows from operations in all periods since inception and had an accumulated deficit of $176.7 million as of December 31, 2021. The Company has historically financed its operations primarily through the sale of convertible notes, redeemable convertible preferred stock and common stock, and payments received from its collaboration arrangement. To date, none of the Company’s product candidates have been approved for sale, and the Company has not generated any revenue from commercial products since inception. Management expects operating losses to continue and increase for the foreseeable future, as the Company progresses into clinical development activities for its lead product candidates. The Company’s prospects are subject to risks, expenses and uncertainties frequently encountered by companies in the biotechnology industry as discussed under Risks and Uncertainties in Note 2. While the Company has been able to raise multiple rounds of financing, there can be no assurance that in the event the Company requires additional financing, such financing will be available on terms which are favorable or at all. Failure to generate sufficient cash flows from operations, raise additional capital or reduce certain discretionary spending would have a material adverse effect on the Company’s ability to achieve its intended business objectives . As of December 31, 2021, the Company had cash, cash equivalents and marketable securities of $368.1 million. Management believes that the Company’s current cash, cash equivalents and marketable securities will be sufficient to fund its planned operations for at least 12 months from the date of the issuance of these financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”). Use of Estimates The preparation of financial statements in conformity with U.S. 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 revenue and expenses during the reporting period. Such estimates include useful lives of property and equipment, determination of the discount rate for operating leases, accruals for research and development activities, revenue recognition, stock-based compensation, and income taxes. On an ongoing basis, management reviews these estimates and assumptions. Changes in facts and circumstances may alter such estimates and actual results could differ from those estimates. Segments The Company operates and manages its business as one operating and reportable segment, which is the business of research and development for oncology-focused precision medicine. The Company’s chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. All of the Company's long-lived assets are located in the United States. Risks and Uncertainties The Company operates in a dynamic and highly competitive industry and is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, protection of proprietary technology, dependence on key personnel, contract manufacturers, contract research organizations and collaboration partners, compliance with government regulations and the need to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical studies and clinical trials and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance and reporting. The Company believes that changes in any of the following areas could have a material adverse effect on the Company’s future financial position, results of operations, or cash flows: ability to obtain future financing; advances and trends in new technologies and industry standards; results of clinical trials and collaboration activities; regulatory approval and market acceptance of the Company’s products; development of sales channels; certain strategic relationships; litigation or claims against the Company based on intellectual property, patent, product, regulatory, or other factors; and the Company’s ability to attract and retain employees necessary to support its growth. Products developed by the Company require approvals from the U.S. Food and Drug Administration (“FDA”) or other international regulatory agencies prior to commercial sales. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained or maintained, that the products will receive the necessary approvals, or that any approved products will be commercially viable. If the Company was denied approval, approval was delayed or the Company was unable to maintain approval, it could have a materially adverse impact on the Company. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from other pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees, consultants and other third parties. Beginning in late 2019, the outbreak of a novel strain of virus named SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), or coronavirus, which causes coronavirus disease 2019, or COVID-19, has evolved into a global pandemic. The extent of the impact of the coronavirus outbreak on the Company’s business will depend on certain developments, including the duration and spread of the outbreak and the extent and severity of the impact on the Company’s clinical trial activities, research activities and suppliers, all of which are uncertain and cannot be predicted. At this point, the extent to which the coronavirus outbreak may materially impact the Company’s financial condition, liquidity or results of operations is uncertain. The Company has expended and will continue to expend substantial funds to complete the research, development and clinical testing of product candidates. The Company also will be required to expend additional funds to establish commercial-scale manufacturing arrangements and to provide for the marketing and distribution of products that receive regulatory approval. The Company may require additional funds to commercialize its products. The Company is unable to entirely fund these efforts with its current financial resources. If adequate funds are unavailable on a timely basis from operations or additional sources of financing, the Company may have to delay, reduce the scope of or eliminate one or more of its research or development programs which would materially and adversely affect its business, financial condition and operations. Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents, marketable securities and accounts receivable. Substantially all the Company’s cash is held by two financial institutions that management believes are of high credit quality. Such deposits may, at times, exceed federally insured limits. The Company’s investment policy addresses credit ratings, diversification, and maturity dates. The Company invests its cash equivalents and marketable securities in money market funds, U.S. government securities, commercial paper, and corporate bonds. The Company limits its credit risk associated with cash equivalents and marketable securities by placing them with banks and institutions it believes are creditworthy and in highly rated investments and, by policy, limits the amount of credit exposure with any one commercial issuer. The Company has not experienced any credit losses on its deposits of cash, cash equivalents or marketable securities. Accounts receivable represents amounts due from GlaxoSmithKline. The Company monitors economic conditions to identify facts or circumstances that may indicate that any of its accounts receivable are at risk of collection. Cash Equivalents Cash equivalents that are readily convertible to cash are stated at cost, which approximates fair value. The Company considers all highly liquid investments purchased with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. Restricted Cash Restricted cash as of December 31, 2021 and December 31, 2020 consisted of cash balances held as security in connection with the Company’s facility lease agreement in South San Francisco, California. The balances are classified as long-term assets on the Company’s balance sheet. Marketable Securities Marketable securities are investments in marketable securities with maturities greater than three months at the time of purchase. The Company determines the appropriate classification of its investments in marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified and accounted for its marketable securities as available-for-sale. After consideration of the Company’s risk versus reward objectives and liquidity requirements, the Company may sell these securities prior to their stated maturities. The Company classifies highly liquid securities with maturities beyond 12 months as long-term marketable securities in the balance sheet. These securities are carried at fair value as determined based upon quoted market prices or pricing models for similar securities. Unrealized gains and losses, if any, are excluded from earnings and are reported as a component of accumulated other comprehensive income (loss). The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income on the statements of operations and comprehensive loss. Realized gains and losses, if any, on available-for-sale securities are included in interest income and other income (expense), net. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. The Company did not identify any of its marketable securities as other-than-temporarily impaired as of December 31, 2021 . Fair Value of Financial Instruments The carrying amounts of the Company’s certain financial instruments, including cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities and market interest rates if applicable. Refer to Note 3 for details on the fair value of marketable securities. Property and Equipment, Net Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which is generally between three and five years. Leasehold improvements are stated at cost and amortized over the shorter of the useful lives of the assets or the lease term Impairment of Long-Lived Assets The Company reviews property and equipment for 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 amount of the asset or asset group to the future net cash flows which the asset or asset group is expected to generate. If such asset or asset group is considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset or asset group exceeds the fair value of the asset or asset group. There have been no such impairments of long-lived assets for the years ended December 31, 2021 and December 31, 2020. Leases T he Company determines if an arrangement is a lease, or contains a lease, at its inception. Operating leases are included in right-of-use (“ROU”) assets, lease liabilities, and long-term lease liabilities on the Company’s balance sheet. ROU assets and lease liabilities are recognized based on the present value of the future lease payments over the lease term at commencement date. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The ROU asset also includes any lease payments made to the lessor at or before the commencement date, minus lease incentives received, and initial direct costs incurred. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company combines lease and nonlease components. Cloud Computing Arrangements The Company capitalizes certain implementation costs incurred under a cloud computing arrangement that is a service contract. Costs incurred during the application development stage related to the implementation of the hosting arrangement are capitalized and included within prepaid expenses and other current assets, and other non-current assets on the accompanying balance sheets. Amortization of capitalized implementation costs is recognized on a straight-line basis over the term of the associated hosting arrangement when it is ready for its intended use. Costs related to preliminary project activities and post-implementation activities are expensed as incurred. Revenue Recognition The Company follows Accounting Standards Codification Topic 606, Revenue from Contracts with Customers The Company applies the five-step model to contracts when (1) parties have approved the contract and are committed to performing respective obligations, (2) the Company can identify each party’s rights regarding the goods or services to be transferred, (3) the Company can identify the payment terms for the goods or services to be transferred, (4) the contract has commercial substance, and (5) it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, the Company assesses the goods or services promised within each contract and determines the performance obligations by assessing whether each promised good or service is distinct. Goods or services that are not distinct are bundled with other goods or services in the contract until a bundle of goods or services that is distinct is created. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligations when (or as) the performance obligations are satisfied. The Company constrains its estimate of the transaction price up to the amount (the “variable consideration constraint”) that a significant reversal of recognized revenue is not probable. Licenses of intellectual property: If a license to the Company’s intellectual property is determined to be distinct from the other promised goods or services identified in an arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license at the point in time 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 goods or services, the Company applies 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 progress toward satisfying the performance obligation for purposes of recognizing revenue from non-refundable, upfront fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of progress and related revenue recognition. Customer options for additional goods or services: If a contract contains customer options that allow the customer to acquire additional goods or services, including a license to the Company’s intellectual property, the goods and services underlying the customer options are evaluated to determine whether they are deemed to represent a material right. In determining whether the customer option has a material right, the Company assesses whether there is an option to acquire additional goods or services at a discount. If the customer option is determined not to represent a material right, the option is not considered to be a performance obligation. If the customer option is determined to represent a material right, the material right is recognized as a separate performance obligation. The Company allocates the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until the option is exercised. Milestone payments: At the inception of each arrangement or amendment that includes development, regulatory or commercial 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. ASC 606 prescribes two methods to use when estimating the amount of variable consideration: the expected value method and the most likely amount method. Under the expected value method, an entity considers the sum of probability-weighted amounts in a range of possible consideration amounts. Under the most likely amount method, an entity considers the single most likely amount in a range of possible consideration amounts. The Company uses the expected value method to estimate the amount of variable consideration related to the reimbursement of PolQ and WRN program costs which is consistently applied throughout the life of the contract: however, it is not necessary for the Company to use the same approach for all contracts. If it is probable that a significant revenue reversal would not occur when the uncertainty associated with the milestone is resolved, the associated milestone value is included in the transaction price. Milestone payments that are highly susceptible to factors outside the Company’s influence, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. If there is more than one performance obligation, the transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability or achievement of each milestone and any related constraint, and if necessary, adjusts its estimates of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Royalties: For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Upfront payments and fees are recorded as contract liabilities upon receipt or when due and may require deferral of revenue recognition to a future period until the Company performs its obligations under these arrangements. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. Contractual cost sharing payments received from a customer or collaboration partner are accounted for as variable consideration. The Company includes an expected value in the transaction price. Contractual cost sharing payments made to a customer or collaboration partner are accounted for as a reduction to the transaction price if such payments are not related to distinct goods or services received from the customer or collaboration partner. Contracts may be amended to account for changes in contract specifications and requirements. Contract modifications exist when the amendment either creates new, or changes existing, enforceable rights and obligations. When contract modifications create new performance obligations and the increase in consideration approximates the standalone selling price for goods and services related to such new performance obligations as adjusted for specific facts and circumstances of the contract, the modification is accounted for as a separate contract. If a contract modification is not accounted for as a separate contract, the Company accounts for the promised goods or services not yet transferred at the date of the contract modification (the remaining promised goods or services) prospectively, as if it were a termination of the existing contract and the creation of a new contract, if the remaining goods or services are distinct from the goods or services transferred on or before the date of the contract modification. The Company accounts for a contract modification as if it were a part of the existing contract if the remaining goods or services are not distinct and, therefore, form part of a single performance obligation that is partially satisfied at the date of the contract modification. In such case , the effect that the contract modification has on the transaction price, and on the entity’s measure of progress toward complete satisfaction of the performance obligation, is recognized as an adjustment to revenue (either as an increase in or a reduction of revenue) at the date of the contract modification (the adjustment to revenue is made on a cumulative catch-up basis). Upfront payment contract liabilities resulting from the Company’s license and collaboration agreements do not represent a financing component as the payment is not financing the transfer of goods and services, and the technology underlying the licenses granted reflects research and development expenses already incurred by the Company. As such, the Company does not adjust its revenues for the effects of a significant financing component. Am Research and Development Expenses Research and development expenses consist of compensation costs, employee benefit costs, costs for contract manufacturing organizations (“CMOs”), costs for contract research organizations (“CROs”), costs for sponsored research, consulting costs, costs for laboratory supplies, costs for product licenses, facility-related expenses and depreciation. All research and development costs are charged to research and development expenses as incurred and included within the statements of operations and comprehensive loss. Payments associated with licensing agreements to acquire exclusive licenses to develop, use, manufacture and commercialize products that have not reached technological feasibility and do not have alternate commercial use are also expensed as incurred. Payments made to third parties under these arrangements in advance of the performance of the related services by the third parties are recorded as prepaid expenses until the services are rendered. Accrued Research and Development Expenses The Company has entered into various agreements with CMOs and CROs. The Company’s research and development accruals are estimated based on the level of services performed, progress of the studies, including the phase or completion of events, and contracted costs. The estimated costs of research and development provided, but not yet invoiced, are included in accrued liabilities on the balance sheet. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments made to CMOs and CROs under these arrangements in advance of the performance of the related services are recorded as prepaid expenses and other current assets until the services are rendered. Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees and non-employees in accordance with ASC 718, Stock Compensation. Income Taxes The Company accounts for income taxes using the asset and liability method whereby deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are currently in effect unless such rate is expected to be different when the deferred item reverses. Valuation allowances are established where necessary to reduce deferred tax assets to the amounts expected to be realized. Deferred tax assets and liabilities are classified as noncurrent on the balance sheet. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that has a greater than 50% likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to unrecognized tax benefits in interest expense and other expense, respectively. Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ equity that are excluded from net loss, primarily unrealized gains and losses from the Company’s marketable securities. Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share 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, stock options, restricted stock and restricted stock that is subject to repurchase at the original purchase price are considered to be potentially dilutive securities. The Company 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 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 common share is the same as basic net loss per common share for those periods. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) under its accounting standard codifications (“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 December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and improves consistent application of and simplifies GAAP for other areas of Topic 740 by clarifying existing guidance. For public business entities, this ASU is effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted. The Company adopted this ASU on January 1, 2021. The adoption did not result in a material impact on the Company’s financial statements and related disclosures. New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Codification Improvements to Topic 326, Financial Instruments—Credit Losses

Fair Value Measurement and Mark

Fair Value Measurement and Marketable Securities	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurement and Marketable Securities	3. Fair Value Measurement and Marketable Securities The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows: Level 1—Observable inputs, such as quoted prices in active markets for identical assets or liabilities at the measurement date . Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities . Level 3—Unobservable inputs which reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model . In determining fair value, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value. As of December 31, 2021, financial assets measured and recorded at fair value are as follows (in thousands): December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Assets U.S. government securities Level 1 $ 122,657 $ — $ (592 ) $ 122,065 Corporate bonds Level 2 76,628 8 (127 ) 76,509 Commercial paper Level 2 77,444 — (1 ) 77,443 Marketable securities 276,729 8 (720 ) 276,017 Money market funds ( 1) Level 1 91,825 — — 91,825 Total fair value of assets $ 368,554 $ 8 $ (720 ) $ 367,842 (1) Included in cash and cash equivalents on the balance sheet As of December 31, 2020, financial assets measured and recognized at fair value are as follows (in thousands): December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Assets U.S. government securities Level 1 $ 80,020 $ 10 $ — $ 80,030 Corporate bonds Level 2 72,573 11 (14 ) 72,570 Commercial paper Level 2 63,948 — — 63,948 Marketable securities 216,541 21 (14 ) 216,548 Money market funds ( 1) Level 1 67,065 — — 67,065 Total fair value of assets $ 283,606 $ 21 $ (14 ) $ 283,613 (1) Included in cash and cash equivalents on the balance sheet As of December 31, 2021, all marketable securities had a remaining maturity of less than two years. As of December 31, 2020, all marketable securities had a remaining maturity of one year or less. There were no financial liabilities measured and recognized at fair value as of December 31, 2021 and December 31, 2020.

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	4. Balance Sheet Components Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): Useful Life As of December 31, (In Years) 2021 2020 Laboratory equipment 5 $ 6,440 $ 4,793 Computer equipment 3 117 117 Software 3 204 118 Leasehold improvements Shorter of useful life or lease term 3,133 2,716 Furniture and fixtures 5 466 421 Total property and equipment 10,360 8,165 Less: Accumulated depreciation and amortization (5,597 ) (3,894 ) Property and equipment, net $ 4,763 $ 4,271 Depreciation and amortization expense was $1.7 million and $1.2 million for the years ended December 31, 2021, Accrued Liabilities Accrued liabilities consisted of the following (in thousands): As of December 31, 2021 2020 Accrued research and development expenses $ 7,864 $ 5,259 Accrued salaries and benefits 3,971 2,685 Legal and professional fees 485 543 Other — 29 Accrued liabilities $ 12,320 $ 8,516

Operating Leases

Operating Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Operating Leases	5. Operating Leases The Company leases its laboratory and office facilities in South San Francisco, California under a non-cancelable operating lease with expiration date in July 2024 On September 30, 2019, the Company and the landlord of the laboratory and office facilities in South San Francisco entered into a second amendment (“Second Amendment”) to lease additional office spaces at the same location. The Company accounts for the Second Amendment as a separate contract and recognized a related right-of-use (“ROU”) asset and lease liability of $1.2 million on the lease commencement date in August 2020. The maturities of operating lease liabilities as of December 31, 2021 are as follows (in thousands): As of December 31, 2021 Operating Leases 2022 $ 1,982 2023 2,036 2024 1,647 Total lease payments 5,665 Less: Interest (484 ) Present value of lease liabilities $ 5,181 Amounts recognized on the balance sheet Current lease liabilities $ 1,699 Long-term lease liabilities 3,482 Total lease liabilities $ 5,181 Operating lease cost was $1.7 million, $1.5 million and $1.5 million for the years ended December 31, 2021, December 31, 2020 and December 31, 2019, respectively. As of December 31, 2021 million are included in current liabilities and non-current liabilities on the balance sheet. As of December 31, 2021, the remaining term for the operating lease in South San Francisco, California is 2.6 years, and the discount rate used to measure the lease liability for such operating lease upon recognition is 7.0% for the Original Lease and 6.0% for the Second Amendment. The Company has one right to extend the lease term of the operating lease in South San Francisco for two years by giving the landlord written notice. The remaining term does not include the additional two years, as the Company assessed at commencement date that it was not reasonably certain to extend the lease term. During the years ended December 31, 2021, December 31, 2020 included in cash flows from operating activities on the statement of cash flows.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Contingencies 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 future expenditures will be made and these expenditures can be reasonably estimated. As of December 31, 2021 . Indemnification The Company enters into standard indemnification arrangements in the ordinary course of business with vendors, clinical trial sites and other parties. 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. 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 never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. Accordingly, the Company has not recorded a liability related to such indemnification agreements as of December 31, 2021.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes No , December 31, 2020 and December 31, 2019. The Company has incurred net operating losses only in the United States since its inception. The Company has not reflected any benefit of such net operating loss carryforwards in the financial statements. The provision for income taxes differs from the amount expected by applying the federal statutory rate to the loss before taxes as follows: Year Ended December 31, 2021 2020 2019 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % State income taxes 0.7 % (1.9 %) 7.0 % Change in valuation allowance (25.2 %) (21.5 %) (31.4 %) Research tax credits 3.8 % 2.7 % 3.6 % Other permanent differences (0.3 %) (0.3 %) (0.4 %) Change in fair value of redeemable convertible preferred stock liability 0.0 % 0.0 % 0.2 % Provision for income taxes 0.0 % 0.0 % 0.0 % The tax effects of temporary differences and carryforwards of the deferred As of December 31, 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 27,324 $ 13,418 Research and development credit carryforwards 5,939 3,813 Lease liability 1,097 1,420 Intangible assets 1,179 1,274 Stock-based compensation 1,725 705 Accruals and reserves 882 505 Deferred revenue 12,575 17,332 Gross deferred tax assets 50,721 38,467 Less: Valuation allowance (49,575 ) (36,879 ) Deferred tax assets, net of valuation allowance 1,146 1,588 Deferred tax liabilities: Right-of-use assets (825 ) (1,100 ) Property and equipment (321 ) (488 ) Net deferred tax assets $ — $ — The Company has established a full valuation allowance against its deferred tax assets due to the uncertainty surrounding the realization of such assets. ASC 740 requires that the tax benefit of net operating losses, temporary differences and credit carryforwards be recorded as an asset to the extent that management assesses that realization is “more likely than not.” Realization of the future tax benefits is dependent on the Company’s ability to generate sufficient taxable income within the carryforward period. Because of the Company’s recent history of operating losses, management believes that recognition of the deferred tax assets arising from the above-mentioned future tax benefits is currently not likely to be realized and, accordingly, has provided a valuation allowance. As of December 31, 2021, the Company had net operating loss carryforwards of $101.6 million available to reduce future taxable income, if any, for federal income tax purposes. As of December 31, 2021, the Company had net operating loss carryforwards of $85.3 million available to reduce future taxable income, if any, for California state income tax purposes. If not utilized, the federal carryforwards of $11.6 million and the state carryforwards of $85.3 million will begin to expire in 2037 and 2036, respectively. The federal net operating loss carryforwards of $90.0 million arising after December 31, 2017 do not expire. The Company also had federal and state research and development credit carryforwards of $4.2 million and $3.7 million, respectively, as of December 31, 2021. The federal credits will expire starting in 2037 if not utilized, and the state research credit can be carried forward indefinitely. The Tax Reform Act of 1986 limits the use of net operating loss carryforwards in certain situations where changes occur in the stock ownership of a company. The annual limitation may result in the expiration of net operating losses and credits before utilization. The Company performed a Section 382 analysis through December 31, 2021. Related to unrecognized tax benefits noted below, the Company accrued no penalties or interest during the years ended December 31, 2021, December 31, 2020 and December 31, 2019. The Company does not expect its unrecognized tax benefit balance to change materially over the next 12 months. The Company had $1.3 million and $0.9 million of unrecognized tax benefits as of December 31, 2021 and December 31, 2020, respectively. The following table summarizes the activity related to the Company’s unrecognized tax benefits (in thousands). Balance as of January 1, 2020 $ 746 Increase related to prior year tax positions 2 Increase related to current year tax positions 153 Balance as of December 31, 2020 $ 901 Increase related to prior year tax positions 73 Increase related to current year tax positions 330 Balance as of December 31, 2021 $ 1,304 The Company files income tax returns in the U.S. federal jurisdiction and in California. For jurisdictions in which tax filings have been filed, all tax years remain open for examination by the federal and California state authorities for three and four years, respectively, from the date of utilization of any net operating losses or credits.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2021
Stockholders Equity Note [Abstract]
Common Stock	8. Common Stock As of December 31, 2021 and December 31, 2020, the Company’s certificate of incorporation authorized the Company to issue 300,000,000 shares of common stock 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 Company’s board of directors. As of December 31, 2021, no dividends have been declared to date. The Company had reserved common stock for future issuance as follows: As of December 31, 2021 2020 Exercise of outstanding options under the 2015 and 2019 Plans 3,620,666 2,591,456 Issuance of common stock options under the 2019 Plan 922,826 975,135 Issuance of common stock options under the Employee Stock Purchase Plan 602,935 357,600 Total 5,146,427 3,924,191

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation 2019 Incentive Award Plan In May 2019, the Company’s board of directors adopted and the Company’s stockholders approved the 2019 Incentive Award Plan (the “2019 Plan”), under which the Company may grant cash and equity-based incentive awards to the Company’s employees, consultants and directors. Following the effectiveness of the 2019 Plan, the Company will not make any further grants under the 2015 Equity Incentive Plan (the “2015 Plan”). However, the 2015 Plan continues to govern the terms and conditions of the outstanding awards granted under it. Shares of common stock subject to awards granted under the 2015 Plan that are forfeited or lapse unexercised and which following the effective date of the 2019 Plan are not issued under the 2015 Plan will be available for issuance under the 2019 Plan. Options granted under the 2019 Plan may be either incentive stock options (“ISOs”) or nonqualified stock options (“NSOs”). ISOs may be granted only to Company employees (including officers and directors who are also employees). NSOs may be granted to Company employees and consultants. The exercise price of an ISO and NSO shall not be less than 100% of the estimated fair value of the shares on the date of grant. The exercise price of an ISO granted to an employee who, at the time of grant, owns stock representing more than 10% of the voting power of all classes of stock of the Company (a “10% stockholder”) shall be no less than 110% of the estimated fair value of the shares on the date of grant. Options granted under the 2019 Plan have a term of 10 years (or five years if granted to a 10% stockholder) and generally vest over a 4-year period with 1-year cliff vesting. 2015 Equity Incentive Plan In 2015, the Company established its 2015 Plan which provides for the granting of stock options to employees and consultants of the Company. Options granted under the 2015 Plan may be either ISOs or NSOs. 2019 Employee Stock Purchase Plan In May 2019, the Company’s board of directors adopted and the Company’s stockholders approved the 2019 Employee Stock Purchase Plan (the “ESPP”). The ESPP provides eligible employees with the opportunity to acquire an ownership interest in the Company through periodic payroll deductions up to 15% of eligible compensation. The offering period is determined by the Company in its discretion but may not exceed 27 months. The per-share purchase price on the applicable exercise date for an offering period is equal to the lesser of 85% of the fair market value of the common stock at either the first business day or last business day of the offering period, provided that no more than 4,000 shares of common stock may be purchased by any one employee during each offering period. The ESPP is intended to constitute an “employee stock purchase plan” under Section 423(b) of the Internal Revenue Code of 1986, as amended. A total of 195,000 shares of common stock were initially reserved for issuance under the ESPP, subject to an annual increase on January 1 of each year, beginning on January 1, 2020. For the years ended December 31, 2021 and December 31, 2020, the Company recorded $0.3 million and $0.2 million of compensation expense related to employee participation in the ESPP. Stock-Based Compensation Expense Total stock-based compensation expense recorded related to awards granted to employees and non-employees was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Research and development $ 3,492 $ 1,234 $ 956 General and administrative 4,745 2,375 1,212 Total stock-based compensation expense $ 8,237 $ 3,609 $ 2,168 Stock Options Activity under the Company’s 2015 and 2019 Plans is set forth below: Outstanding Options Shares available for Grant Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Balance, January 1, 2021 975,135 2,591,456 $ 7.27 8.36 $ 15.70 Additional shares authorized 1,181,488 — Options granted (1,560,425 ) 1,560,425 $ 20.52 Options exercised — (211,900 ) $ 7.13 Options repurchased — — Options canceled 326,628 (319,315 ) $ 14.33 Balance, December 31, 2021 922,826 3,620,666 $ 12.36 7.92 $ 41.40 Exercisable as of December 31, 2021 1,498,708 $ 6.58 6.60 $ 25.70 Vested and expected to vest as of December 31, 2021 3,620,666 $ 12.36 7.92 $ 41.40 The weighted-average grant-date fair value of options granted during the years ended December 31, 2021 and December 31, 2020 was $16.09 and $6.16 per share, respectively. The aggregate intrinsic value of options exercised for the years ended December 31, 2021 and December 31, 2020 was $3.5 million and $1.7 million, respectively. Intrinsic values are calculated as the difference between the exercise price of the underlying options and the fair value of the common stock on the date of exercise. As of December 31, 2021, the total unrecognized stock-based compensation expense for stock options was $22.2 million, which is expected to be recognized over a weighted-average period of 2.61 years. Early Exercise of Stock Options The terms of the 2015 Plan permit the exercise of options granted under the 2015 Plan prior to vesting, subject to required approvals. The shares so acquired prior to vesting are subject to a lapsing repurchase right in favor of the Company at the original purchase price of such shares, exercisable upon a termination of the holder’s service with the Company prior to full vesting. The proceeds are initially recorded in other liabilities from the early exercise of stock options and are reclassified to additional paid-in capital as the Company’s repurchase right lapses. During the years ended December 31, 2021 and December 31, 2020, the Company repurchased zero and 10,518 shares of common stock, respectively. As of December 31, 2021 and December 31, 2020, shares that were subject to repurchase were zero and 14,460, respectively. The aggregate exercise price of early exercised shares as of December 31, 2021 and December 31, 2020 was zero and less than $0.1 million, respectively, which were recorded in other current liabilities and other non-current liabilities. Black-Scholes Assumptions The fair values of options were calculated using the assumptions set forth below: Year Ended December 31, 2021 2020 2019 Expected term 5.5 - 6.1 years 5.5 - 6.1 years 5.4 - 6.1 years Expected volatility 90.0% - 103.6% 84.9 % - 98.3% 77.2% - 85.5% Risk-free interest rate 0.6% - 1.4% 0.3% - 1.5% 1.4% - 2.5 % Dividend yield 0% 0% 0% Expected term . The expected term represents the weighted-average period the stock options are expected to remain outstanding and is based on the options’ vesting terms, contractual terms and industry peers, as the Company does not have sufficient historical information to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior. Expected Volatility . As there is insufficient trading history for the Company’s common stock, the Company bases its computation of expected volatility on the historical stock price volatility of its own common stock and that of a representative peer group of public companies with similar characteristics to the Company. For purposes of identifying these peer companies, the Company considers the industry, stage of development, size and financial leverage of potential comparable companies. The historical volatility is calculated based on a period of time commensurate with the expected term assumption for each grant. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. Risk-Free Interest Rate . The risk-free rate assumption is based on U.S. Treasury instruments whose term was consistent with the expected term of the Company’s stock options. Expected Dividend Rate . The Company has not paid and does not anticipate paying any dividends in the near future. Accordingly, the Company has estimated the dividend yield to be zero. The Company accounts for forfeitures as they occur. Fair Value of Common Stock The fair value of the Company’s common stock is determined based on its closing market price on the date of grant. Restricted Stock Restricted stock activity was as follows: Number of Shares Underlying Outstanding Restricted Stock Awards Weighted Average Grant Date Fair Value Unvested, December 31, 2020 14,625 $ 0.82 Vested (7,312 ) $ 0.82 Repurchased (7,313 ) $ 0.82 Unvested, December 31, 2021 — As of December 31, 2021 and December 31, 2020, zero shares and 14,625 shares of restricted stock, respectively, were outstanding with an aggregate purchase price of zero and less than $0.1 million, respectively, which is recorded in other non-current liabilities on the balance sheets. The restricted stock vests upon the achievement of pre-defined research milestones. The holder of restricted stock has voting and dividend rights with respect to such shares held without regard to vesting. Shares of restricted stock are subject to a right of repurchase at the original purchase price held by the Company. As the restricted stock was purchased by an employee at a price equal to its fair value at the time of issuance, there was no stock-based compensation expense related to these awards. The total fair value of restricted stock vested during the years ended December 31, 2021 and December 31, 2020 was $0.1 million and zero, respectively.

Significant Agreements

Significant Agreements	12 Months Ended
	Dec. 31, 2021
Significant Agreements [Abstract]
Significant Agreements	10. Significant Agreements GlaxoSmithKline Collaboration, Option and License Agreement In June 2020, the Company entered into a Collaboration, Option and License Agreement, or the GSK Collaboration Agreement, with an affiliate of GlaxoSmithKline, GLAXOSMITHKLINE INTELLECTUAL PROPERTY (NO. 4), Limited, or GSK, pursuant to which the Company and GSK have entered into a collaboration for its synthetic lethality programs targeting methionine adenosyltransferase 2a, or MAT2A, DNA Polymerase Theta, or Pol Theta or POLQ, and Werner Helicase, or WRN. On July 27, 2020 (“Effective Date”), the Company and GSK received Hart-Scott-Rodino Antitrust Improvements Act clearance, or HSR Clearance, and the GSK Collaboration Agreement became effective. Pursuant to the GSK Collaboration Agreement, GSK paid the Company $100.0 million (the “Upfront Payment”) on July 31, 2020. MAT2A Program For the MAT2A program, the Company will lead research and development through early clinical development. GSK has an exclusive option to obtain an exclusive license to continue development of and commercialize MAT2A products arising out of the MAT2A program, or the Option, exercisable within a specified time period after the Company delivers to GSK a data package resulting from its conduct of a dose escalation portion of a MAT2A Phase 1 monotherapy clinical trial. At such time of exercise, GSK has agreed to pay the Company an option exercise payment of $50.0 million. GSK may initiate, or request that the Company initiates, a Phase 1 combination clinical trial for a MAT2A product and GSK’s Type I PRMT inhibitor (GSK3368715) product, or the MAT2A Combination Trial, prior to GSK’s exercise of the Option. The Company will be responsible for the costs of research and early clinical development activities that the Company conducts for the MAT2A program prior to GSK’s exercise of the Option, excluding the costs of conducting the MAT2A Combination Trial. GSK will be solely responsible for costs of the conduct of the MAT2A Combination Trial, except for supply of the MAT2A product therefor, to be provided by the Company at its own cost. As of December 31, 2021, GSK has neither initiated nor requested that the Company initiate the MAT2A Combination Trial. Subject to GSK’s exercise of the Option, GSK will lead later stage global clinical development for the MAT2A program, with IDEAYA responsible for 20% and GSK responsible for 80% of further development costs. The cost-sharing percentages will be adjusted based on the actual ratio of U.S. to global profits for MAT2A products, as measured three and six years after global commercial launch thereof. Subject to GSK’s exercise of the Option, the Company will be eligible to receive future development and regulatory milestones of up to $465.0 million, and commercial milestones of up to $475.0 million, with respect to each MAT2A product. Additionally, the Company is entitled to receive 50% of U.S. net profits and tiered royalties on global non-U.S. net sales of MAT2A products by GSK, its affiliates and their sublicensees ranging from high single digit to sub-teen double digit percentages, subject to certain customary reductions. The Company will have a right to opt-out U.S. net profit share and corresponding development cost share for the MAT2A program, in which case the Company would be eligible to receive tiered royalties on U.S. net sales of MAT2A products by GSK, its affiliates and their sublicensees at the same royalty rates as for global non-U.S. net sales thereafter, with economic adjustments based on the stage of the MAT2A program at the time of opt-out Pol Theta Program Pursuant to the GSK Collaboration Agreement, GSK holds a global, exclusive license to develop and commercialize POLQ products arising out of the POLQ program. GSK and the Company will collaborate on ongoing preclinical research for the POLQ program, and GSK will lead clinical development for the POLQ program. GSK will be responsible for all research and development costs for the POLQ program, including those incurred by the Company. The Company will be eligible to receive future development and regulatory milestones of up to $485.0 million, with respect to each POLQ product, including as applicable, for multiple POLQ products that target certain alternative protein domains or are based on alternative modalities. Additionally, the Company is eligible to receive up to $475.0 million of commercial milestones with respect to each POLQ product. The Company is also entitled to receive tiered royalties on global net sales of POLQ products by GSK, its affiliates and their sublicensees ranging from high single digit to sub-teen double digit percentages, subject to certain customary reductions. WRN Program Pursuant to the GSK Collaboration Agreement, GSK holds a global, exclusive license to develop and commercialize WRN products arising out of the WRN program. The Company and GSK will collaborate on ongoing preclinical research for the WRN program, and GSK will lead clinical development for the WRN program, with IDEAYA responsible for 20 The Company will be eligible to receive future development milestones of up to $485.0 million, with respect to each WRN product, including as applicable, for multiple WRN products that are based on alternative modalities. Additionally, the Company will be eligible to receive up to $475.0 million of commercial milestones with respect to each WRN product. The Company will be entitled to receive 50% of U.S. net profits and tiered royalties on global non-U.S. net sales of WRN products by GSK, its affiliates and their sublicensees ranging from high single digit to sub-teen double digit percentages, subject to certain customary reductions. The Company will have a right to opt-out of U.S. net profit share and corresponding research and development cost share for the WRN program, and would be eligible to receive tiered royalties on U.S. net sales of WRN products by GSK, its affiliates and their sublicensees at the same royalty rates as for global non-U.S. net sales thereafter, with economic adjustments based on the stage of the WRN program at the time of opt-out General Under the terms of the GSK Collaboration Agreement, subject to certain exceptions, the Company and GSK will not, directly or through third parties, develop or commercialize other products whose primary and intended mechanism of action is the modulation of WRN, POLQ, or MAT2A (unless GSK does not exercise the Option, in which case such restriction shall cease to apply with respect to MAT2A) for an agreed upon period of time. The Company and GSK will form a joint steering committee, joint development committees, and joint commercialization committees responsible for coordinating all activities under the GSK Collaboration Agreement. Ownership of intellectual property developed under the GSK Collaboration Agreement is allocated between or shared by the parties depending on development and subject matter. GSK’s royalty obligations continue with respect to each country and each product until the later of (i) the date on which such product is no longer covered by certain intellectual property rights in such country and (ii) the 10th anniversary of the first commercial sale of such product in such country. Each party has the right to sublicense its rights under the GSK Collaboration Agreement subject to certain conditions. The GSK Collaboration Agreement will continue in effect on a product-by-product and country-by-country basis until the expiration of the obligation to make payments under the GSK Collaboration Agreement with respect to such product in each country, unless earlier terminated by either party pursuant to its terms. Either the Company or GSK may terminate the GSK Collaboration Agreement for the other party’s insolvency or certain uncured breaches. The Company may terminate the GSK Collaboration Agreement if GSK or any of its sublicensees or affiliates challenge certain patents of the Company. GSK may terminate the GSK Collaboration Agreement in its entirety or on a target-by-target basis upon 90 Pfizer Clinical Trial Collaboration and Supply Agreement In March 2020, the Company entered into a clinical trial collaboration and supply agreement with Pfizer Inc., or the Supply Agreement, as amended in September 2020, April 2021 and August 2021. Pursuant to the Supply Agreement, Pfizer supplies the Company with their MEK inhibitor, binimetinib, and cMET inhibitor, crizotinib, to evaluate combinations of darovasertib independently with each of the Pfizer compounds, in patients with tumors harboring activating GNAQ or GNA11 hotspot mutations. Under the Supply Agreement, the Company will sponsor a Phase 1/2 clinical trial, and Pfizer will supply the Company with binimetinib and crizotinib for use in the clinical trial at no cost to the Company. The Supply Agreement provides that the Company and Pfizer will jointly own clinical data generated from the clinical trial. Novartis In September 2018, the Company entered into a license agreement with Novartis International Pharmaceuticals Ltd. (“Novartis”) to develop and commercialize Novartis’ LXS196 (also known as IDE196), a Phase 1 protein kinase C (“PKC”) inhibitor for the treatment of cancers having GNAQ and GNA11 mutations. Under the license agreement, the Company is liable to make contingent development and sales milestone payments of up to $29.0 million and mid to high single digit royalty payments of the net sales of licensed products. As of December 31, 2021, the Company has not achieved any of the development and sales milestones.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2021
Revenue From Contract With Customer [Abstract]
Revenue Recognition	11. Revenue Recognition The Company recognizes revenue in accordance with ASC 606 for the GSK Collaboration Agreement (see No. 10, Significant Agreements). Disaggregation of Revenue The following table presents revenue disaggregated by research program (in thousands): Year Ended December 31, 2021 2020 MAT2A $ 7,230 $ 6,048 Pol Theta 12,894 7,917 WRN 7,817 5,573 Total collaboration revenue $ 27,941 $ 19,538 Contract balances As of December 31, 2021 and December 31, 2020, the Company had accounts receivable of $1.1 million and $1.9 million, respectively, and contract liabilities of $60.2 million and $83.8 million, respectively, related to the GSK Collaboration Agreement. The following table presents the significant changes in the balance of contract liabilities during the year ended December 31, 2021 Contract liabilities Balance as of December 31, 2020 $ 83,773 Reclassification to revenue, as the result of performance obligations satisfied (27,941 ) Cash received for cost reimbursement 3,414 Increase in accounts receivable 986 Balance as of December 31, 2021 $ 60,232 The timing of revenue recognition, billings, and cash collections results in accounts receivable, contract assets, and contract liabilities on the balance sheets. Based on the estimated reimbursable program costs for a quarter, the Company recognizes accounts receivable, which are derecognized upon reimbursement. When consideration is received, or such consideration is unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a contract, a contract liability is recorded. Contract liabilities are derecognized as revenue after control of the products or services is transferred to the customer and all revenue recognition criteria have been met. Performance obligations The Company has identified the following six performance obligations associated with the GSK Collaboration Agreement: (i) Preclinical and Phase 1 Monotherapy clinical research and development services under the MAT2A program (“MAT2A R&D Services”) (ii) Preclinical research services and the related license to IDEAYA-owned technology under the Pol Theta program (“Pol Theta R&D Services”) (iii) Preclinical research services and the related license to IDEAYA-owned technology under the WRN program (“WRN R&D Services”) (iv) Material right associated with the option to license IDEAYA-owned technology under the MAT2A program (defined as the “Option” in Note 9) (v) Material right associated with the option to license to IDEAYA-owned technology under the MAT2A program to the extent necessary for preclinical activities in preparation for the MAT2A Combination Trial (“Preclinical MAT2A License”) (vi) Material right associated with the supply of MAT2A product for the MAT2A Combination Trial (“MAT2A Supply”) The Company will recognize revenue related to amounts allocated to the MAT2A R&D services as the underlying services are performed over the period through the delivery of the data package, which will be generated from its conduct of the MAT2A Phase 1 monotherapy clinical trial. The Company uses its internal research and development capability and may also engage third-party clinical research organizations, or CROs, in transferring the MAT2A R&D services, for which the Company acts as a principal With respect to the Pol Theta and WRN programs, the Company identified two promises: (1) granting of the license to develop and commercialize Pol Theta and WRN products, respectively, and (2) the preclinical research services. The Company has determined that these two promises are not distinct within the context of the contract. As of the effective date of the GSK Collaboration Agreement, both programs were at an early stage, and the Company was yet to identify any development candidate for either program, which will require the completion of certain preclinical studies. After the Company and GSK identify a development candidate, a series of IND-enabling studies will be conducted before an Investigational New Drug application is submitted to the FDA. Due to the early stage of development, the Company’s preclinical research services are expected to transform the underlying technology and significantly modify or customize the license. Therefore, the two promises are not distinct from each other and are accounted for as a single performance obligation for each of the Pol Theta and WRN programs, respectively. The Company will recognize revenue related to amounts allocated to the Pol Theta R&D Services and WRN R&D Services as the underlying services are performed over the period through the completion of the Pol Theta and WRN preclinical research programs, respectively. Within 90 days from the end of each calendar quarter, GSK will reimburse the Pol Theta program costs incurred by the Company. Within 75 days 75 days Upon exercise of the Option, GSK will obtain the license to develop and commercialize MAT2A products. The Company has concluded that this Option results in a material right as the option exercise fee contains a discount that GSK would not have otherwise received. The Company has determined the nature of the license to develop and commercialize MAT2A products to be functional. After exercise of the Option, the Company will recognize revenue, when it makes the underlying MAT2A technology available to GSK, which will immediately be able to use and benefit from its right to use the intellectual property. The Company has identified two additional customer options under the MAT2A program, both of which have been determined a material right. GSK may elect to conduct certain preclinical activities in preparation for the MAT2A Combination Trial and may elect to exercise the option to license to MAT2A technology. GSK may be able to use and exploit the license to the extent necessary for GSK’s performance of such preclinical activities. The Company will not receive any consideration for providing such license and has concluded that this license option results in a material right as it involves a discount that GSK would not have otherwise received. The Company has determined the nature of such license to MAT2A technology to be functional. Accordingly, the Company recognized revenue from the Preclinical MAT2A License in the year ended December 31, 2020 If GSK elects to conduct the MAT2A Combination Trial, the Company will supply MAT2A product to be used for the MAT2A Combination Trial at its own cost. The Company has concluded that this supply option results in a material right as it involves a discount that GSK would not have otherwise received. The Company will recognize revenue, as it transfers the control of the MAT2A product to GSK . The Company has not supplied MAT2A product as of . Transaction price allocated to the remaining performance obligations The following table presents the transaction price allocated to the remaining performance obligations as of December 31, 2021 Performance Obligations Allocation of Transaction Price MAT2A R&D Services $ 9,486 Pol Theta R&D Services 13,751 WRN R&D Services 20,829 The Option 17,680 MAT2A Supply 2,411 Total transaction price allocated to the remaining performance obligations $ 64,157 The Company applies the sales-based royalty exception to the commercial milestones and tiered royalties for all programs because GSK would ascribe significantly more value to the license than to the other goods or services to which the commercial milestones and tiered royalties relate. The Company will be entitled to receive the commercial milestones either when the first commercial sale occurs, or when the predefined net sales in a calendar year are achieved, upon which the variability will be resolved. Also, the Company will be entitled to receive the tiered royalties during a calendar year when global net sales of each product occur, upon which the variability will be resolved. Significant judgements In applying ASC 606 to the GSK Collaboration Agreement, the Company made the following judgments that significantly affect the timing and amount of revenue recognition: (i) Determination of the transaction price, including whether any variable consideration is included at inception of the contract The transaction price is the amount of consideration that the Company expects to be entitled to in exchange for transferring promised goods or services to the customer. The transaction price must be determined at inception of a contract and may include amounts of variable consideration. However, there is a constraint on inclusion of variable consideration in the transaction price, if there is uncertainty at inception of the contract as to whether such consideration will be recognized in the future. The decision as to whether or not it is probable that a significant reversal of revenue will occur in the future, depends on the likelihood and magnitude of the reversal and is highly susceptible to factors outside the Company’s influence (for example, the Company cannot determine the outcome of clinical trials; the Company cannot determine if or when the counterparty will initiate or complete clinical trials; and the Company cannot determine if or when an regulatory agency provides any approval). In addition, the uncertainty is not expected to be resolved for a long period and finally, the Company has limited experience in the field. Therefore, at inception of the GSK Collaboration Agreement, development and regulatory milestones were fully constrained and were not included in the transaction price based on the factors noted above. The Company constrains estimates of other variable consideration, such as reimbursable program costs, to amounts that are not expected to result in a significant revenue reversal in the future. The Company re-evaluates the transaction price, including the estimated variable consideration included in the transaction price and all constrained amounts, in each reporting period and as uncertain events are resolved or other changes in circumstances occur. (ii) Determination of the estimate of the standalone selling price of performance obligations In order to recognize revenue under ASC 606, for contracts for which more than one distinct performance obligation has been identified, the Company must allocate the transaction price to the performance obligations based upon their standalone selling prices. The best evidence of standalone selling price is an observable price of a good or service when sold separately by an entity in similar circumstances to similar customers. If such evidence is not available, standalone selling price should be estimated so that the amount that is allocated to each performance obligation equals the amount that the entity expects to receive for transferring goods or services. The Company has identified more than one performance obligation in the GSK Collaboration Agreement. Since evidence based on observable prices is not available for the performance obligations, the Company considered market conditions and entity-specific factors, including those contemplated in negotiating the agreements, as well as certain internally developed estimates. The Company determined the estimate of standalone selling price of the MAT2A R&D Services by using the expected costs of satisfying the performance obligation, adjusted for probabilities of technical success where appropriate. The Company determined the estimate of standalone selling price of the Pol Theta R&D Services and WRN R&D Services by using a combination of risk-adjusted net present value analysis and (iii) Determination of the method of allocation of the transaction price to the distinct performance obligations At inception of the GSK Collaboration Agreement, the Company allocated the transaction price among the six performance obligations based on their relative selling prices, determined as described above. (iv) Determination of the timing of satisfaction of performance obligations The Company recognizes revenue from the MAT2A R&D Services, Pol Theta R&D Services and WRN R&D Services over time, as GSK simultaneously receives and consumes the benefits provided by the Company’s performance as the Company performs. The Company measures its progress toward complete satisfaction of the MAT2A R&D Services, Pol Theta R&D Services and WRN R&D Services based on the costs incurred as a percentage of the estimated total costs to be incurred to complete the performance obligations. As the Company performs, it shares the results of research and development studies with GSK through the joint development committee. Accordingly, the cost incurred method faithfully depicts the Company’s performance of the MAT2A R&D Services, Pol Theta R&D Services and WRN R&D Services. The license to IDEAYA-owned technology under the MAT2A program underlying the Option and Preclinical MAT2A License is functional in nature. Upon the exercise of the material right associated with the option to license to IDEAYA-owned technology under the MAT2A program, the Company will recognize revenue upon the later of transfer of the underlying technology to GSK and the beginning of the period during which GSK is able to use and benefit from its right to use the underlying technology. After the exercise of the material right associated with the supply of MAT2A product for the MAT2A Combination Trial, the Company will recognize revenue as it transfers the control of MAT2A product to GSK.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	12. 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 (in thousands, except share and per share data): Year Ended December 31, 2021 2020 2019 Numerator: Net loss attributable to common stockholders $ (49,762 ) $ (34,495 ) $ (41,975 ) Denominator: Weighted-average shares outstanding 35,262,987 24,783,287 12,669,367 Less: weighted-average shares of restricted stock that are subject to repurchase (10,544 ) (61,512 ) (172,410 ) Weighted-average shares used in computing net loss per share attributable to common stock, basic and diluted 35,252,443 24,721,775 12,496,957 Net loss per share attributable to common stockholders, basic and diluted $ (1.41 ) $ (1.40 ) $ (3.36 ) The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive: As of December 31, 2021 2020 2019 Options to purchase common stock 3,620,666 2,591,456 1,962,332 Restricted stock — 14,625 14,625 Restricted stock acquired upon early exercise of stock options — 14,460 84,964 Total 3,620,666 2,620,541 2,061,921

401(k) Retirement Savings Plan

401(k) Retirement Savings Plan	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
401(k) Retirement Savings Plan	13. 401(k) Retirement Savings Plan In 2016, the Company adopted a 401(k) plan for all employees who have met certain eligibility requirements. Under the agreement, employees may elect to contribute up to 90% of their eligible compensation to a 401(k) plan, subject to certain limitations. 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 year ended , , the Company made matching contributions of $0.2 million,

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events In January 2022, the Company sold an aggregate of 2,173 shares of its common stock for aggregate net proceeds of $0.05 million at a weighted average sales price of approximately $24.01 per share under the at-the-market offering pursuant to the January 2021 Sales Agreements with Jefferies as sales agent. On January 31, 2022, GSK waived its rights under the GSK Collaboration Agreement to initiate, or request that the Company initiate, prior to GSK’s exercise of the Option, a Phase 1 combination clinical trial for a MAT2A product and GSK’s Type I PRMT inhibitor (GSK3368715) product, or the MAT2A Combination Trial. Accordingly, the Company has no further obligation under the GSK Collaboration Agreement to supply MAT2A product for the MAT2A Combination Trial at its own cost. IDEAYA’s obligation to supply the MAT2A compound under MAT2A Combination Study was deemed a material right under the GSK Collaboration Agreement. See Note 11, Revenue Recognition, for more information. On January 28, 2022, the Company exercised its option for an exclusive worldwide license covering a broad class of PARG inhibitors from Cancer Research Technology Ltd. (CRT) and the University of Manchester, and in connection therewith, paid a one-time option exercise fee of £250,000. The Company will be obligated to make payments to CRT aggregating up to £19.5 million upon the

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. 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 revenue and expenses during the reporting period. Such estimates include useful lives of property and equipment, determination of the discount rate for operating leases, accruals for research and development activities, revenue recognition, stock-based compensation, and income taxes. On an ongoing basis, management reviews these estimates and assumptions. Changes in facts and circumstances may alter such estimates and actual results could differ from those estimates.
Segments	Segments The Company operates and manages its business as one operating and reportable segment, which is the business of research and development for oncology-focused precision medicine. The Company’s chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. All of the Company's long-lived assets are located in the United States.
Risks and Uncertainties	Risks and Uncertainties The Company operates in a dynamic and highly competitive industry and is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, protection of proprietary technology, dependence on key personnel, contract manufacturers, contract research organizations and collaboration partners, compliance with government regulations and the need to obtain additional financing to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical studies and clinical trials and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance and reporting. The Company believes that changes in any of the following areas could have a material adverse effect on the Company’s future financial position, results of operations, or cash flows: ability to obtain future financing; advances and trends in new technologies and industry standards; results of clinical trials and collaboration activities; regulatory approval and market acceptance of the Company’s products; development of sales channels; certain strategic relationships; litigation or claims against the Company based on intellectual property, patent, product, regulatory, or other factors; and the Company’s ability to attract and retain employees necessary to support its growth. Products developed by the Company require approvals from the U.S. Food and Drug Administration (“FDA”) or other international regulatory agencies prior to commercial sales. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained or maintained, that the products will receive the necessary approvals, or that any approved products will be commercially viable. If the Company was denied approval, approval was delayed or the Company was unable to maintain approval, it could have a materially adverse impact on the Company. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from other pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees, consultants and other third parties. Beginning in late 2019, the outbreak of a novel strain of virus named SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), or coronavirus, which causes coronavirus disease 2019, or COVID-19, has evolved into a global pandemic. The extent of the impact of the coronavirus outbreak on the Company’s business will depend on certain developments, including the duration and spread of the outbreak and the extent and severity of the impact on the Company’s clinical trial activities, research activities and suppliers, all of which are uncertain and cannot be predicted. At this point, the extent to which the coronavirus outbreak may materially impact the Company’s financial condition, liquidity or results of operations is uncertain. The Company has expended and will continue to expend substantial funds to complete the research, development and clinical testing of product candidates. The Company also will be required to expend additional funds to establish commercial-scale manufacturing arrangements and to provide for the marketing and distribution of products that receive regulatory approval. The Company may require additional funds to commercialize its products. The Company is unable to entirely fund these efforts with its current financial resources. If adequate funds are unavailable on a timely basis from operations or additional sources of financing, the Company may have to delay, reduce the scope of or eliminate one or more of its research or development programs which would materially and adversely affect its business, financial condition and operations.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents, marketable securities and accounts receivable. Substantially all the Company’s cash is held by two financial institutions that management believes are of high credit quality. Such deposits may, at times, exceed federally insured limits. The Company’s investment policy addresses credit ratings, diversification, and maturity dates. The Company invests its cash equivalents and marketable securities in money market funds, U.S. government securities, commercial paper, and corporate bonds. The Company limits its credit risk associated with cash equivalents and marketable securities by placing them with banks and institutions it believes are creditworthy and in highly rated investments and, by policy, limits the amount of credit exposure with any one commercial issuer. The Company has not experienced any credit losses on its deposits of cash, cash equivalents or marketable securities. Accounts receivable represents amounts due from GlaxoSmithKline. The Company monitors economic conditions to identify facts or circumstances that may indicate that any of its accounts receivable are at risk of collection.
Cash Equivalents	Cash Equivalents Cash equivalents that are readily convertible to cash are stated at cost, which approximates fair value. The Company considers all highly liquid investments purchased with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents.
Restricted Cash	Restricted Cash Restricted cash as of December 31, 2021 and December 31, 2020 consisted of cash balances held as security in connection with the Company’s facility lease agreement in South San Francisco, California. The balances are classified as long-term assets on the Company’s balance sheet.
Marketable Securities	Marketable Securities Marketable securities are investments in marketable securities with maturities greater than three months at the time of purchase. The Company determines the appropriate classification of its investments in marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified and accounted for its marketable securities as available-for-sale. After consideration of the Company’s risk versus reward objectives and liquidity requirements, the Company may sell these securities prior to their stated maturities. The Company classifies highly liquid securities with maturities beyond 12 months as long-term marketable securities in the balance sheet. These securities are carried at fair value as determined based upon quoted market prices or pricing models for similar securities. Unrealized gains and losses, if any, are excluded from earnings and are reported as a component of accumulated other comprehensive income (loss). The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income on the statements of operations and comprehensive loss. Realized gains and losses, if any, on available-for-sale securities are included in interest income and other income (expense), net. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. The Company did not identify any of its marketable securities as other-than-temporarily impaired as of December 31, 2021 .
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of the Company’s certain financial instruments, including cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities and market interest rates if applicable. Refer to Note 3 for details on the fair value of marketable securities.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which is generally between three and five years. Leasehold improvements are stated at cost and amortized over the shorter of the useful lives of the assets or the lease term
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews property and equipment for 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 amount of the asset or asset group to the future net cash flows which the asset or asset group is expected to generate. If such asset or asset group is considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the asset or asset group exceeds the fair value of the asset or asset group. There have been no such impairments of long-lived assets for the years ended December 31, 2021 and December 31, 2020.
Leases	Leases T he Company determines if an arrangement is a lease, or contains a lease, at its inception. Operating leases are included in right-of-use (“ROU”) assets, lease liabilities, and long-term lease liabilities on the Company’s balance sheet. ROU assets and lease liabilities are recognized based on the present value of the future lease payments over the lease term at commencement date. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The ROU asset also includes any lease payments made to the lessor at or before the commencement date, minus lease incentives received, and initial direct costs incurred. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company combines lease and nonlease components.
Cloud Computing Arrangements	Cloud Computing Arrangements The Company capitalizes certain implementation costs incurred under a cloud computing arrangement that is a service contract. Costs incurred during the application development stage related to the implementation of the hosting arrangement are capitalized and included within prepaid expenses and other current assets, and other non-current assets on the accompanying balance sheets. Amortization of capitalized implementation costs is recognized on a straight-line basis over the term of the associated hosting arrangement when it is ready for its intended use. Costs related to preliminary project activities and post-implementation activities are expensed as incurred.
Revenue Recognition	Revenue Recognition The Company follows Accounting Standards Codification Topic 606, Revenue from Contracts with Customers The Company applies the five-step model to contracts when (1) parties have approved the contract and are committed to performing respective obligations, (2) the Company can identify each party’s rights regarding the goods or services to be transferred, (3) the Company can identify the payment terms for the goods or services to be transferred, (4) the contract has commercial substance, and (5) it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, the Company assesses the goods or services promised within each contract and determines the performance obligations by assessing whether each promised good or service is distinct. Goods or services that are not distinct are bundled with other goods or services in the contract until a bundle of goods or services that is distinct is created. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligations when (or as) the performance obligations are satisfied. The Company constrains its estimate of the transaction price up to the amount (the “variable consideration constraint”) that a significant reversal of recognized revenue is not probable. Licenses of intellectual property: If a license to the Company’s intellectual property is determined to be distinct from the other promised goods or services identified in an arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license at the point in time 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 goods or services, the Company applies 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 progress toward satisfying the performance obligation for purposes of recognizing revenue from non-refundable, upfront fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of progress and related revenue recognition. Customer options for additional goods or services: If a contract contains customer options that allow the customer to acquire additional goods or services, including a license to the Company’s intellectual property, the goods and services underlying the customer options are evaluated to determine whether they are deemed to represent a material right. In determining whether the customer option has a material right, the Company assesses whether there is an option to acquire additional goods or services at a discount. If the customer option is determined not to represent a material right, the option is not considered to be a performance obligation. If the customer option is determined to represent a material right, the material right is recognized as a separate performance obligation. The Company allocates the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until the option is exercised. Milestone payments: At the inception of each arrangement or amendment that includes development, regulatory or commercial 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. ASC 606 prescribes two methods to use when estimating the amount of variable consideration: the expected value method and the most likely amount method. Under the expected value method, an entity considers the sum of probability-weighted amounts in a range of possible consideration amounts. Under the most likely amount method, an entity considers the single most likely amount in a range of possible consideration amounts. The Company uses the expected value method to estimate the amount of variable consideration related to the reimbursement of PolQ and WRN program costs which is consistently applied throughout the life of the contract: however, it is not necessary for the Company to use the same approach for all contracts. If it is probable that a significant revenue reversal would not occur when the uncertainty associated with the milestone is resolved, the associated milestone value is included in the transaction price. Milestone payments that are highly susceptible to factors outside the Company’s influence, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. If there is more than one performance obligation, the transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability or achievement of each milestone and any related constraint, and if necessary, adjusts its estimates of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Royalties: For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Upfront payments and fees are recorded as contract liabilities upon receipt or when due and may require deferral of revenue recognition to a future period until the Company performs its obligations under these arrangements. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. Contractual cost sharing payments received from a customer or collaboration partner are accounted for as variable consideration. The Company includes an expected value in the transaction price. Contractual cost sharing payments made to a customer or collaboration partner are accounted for as a reduction to the transaction price if such payments are not related to distinct goods or services received from the customer or collaboration partner. Contracts may be amended to account for changes in contract specifications and requirements. Contract modifications exist when the amendment either creates new, or changes existing, enforceable rights and obligations. When contract modifications create new performance obligations and the increase in consideration approximates the standalone selling price for goods and services related to such new performance obligations as adjusted for specific facts and circumstances of the contract, the modification is accounted for as a separate contract. If a contract modification is not accounted for as a separate contract, the Company accounts for the promised goods or services not yet transferred at the date of the contract modification (the remaining promised goods or services) prospectively, as if it were a termination of the existing contract and the creation of a new contract, if the remaining goods or services are distinct from the goods or services transferred on or before the date of the contract modification. The Company accounts for a contract modification as if it were a part of the existing contract if the remaining goods or services are not distinct and, therefore, form part of a single performance obligation that is partially satisfied at the date of the contract modification. In such case , the effect that the contract modification has on the transaction price, and on the entity’s measure of progress toward complete satisfaction of the performance obligation, is recognized as an adjustment to revenue (either as an increase in or a reduction of revenue) at the date of the contract modification (the adjustment to revenue is made on a cumulative catch-up basis). Upfront payment contract liabilities resulting from the Company’s license and collaboration agreements do not represent a financing component as the payment is not financing the transfer of goods and services, and the technology underlying the licenses granted reflects research and development expenses already incurred by the Company. As such, the Company does not adjust its revenues for the effects of a significant financing component. Am
Research and Development Expenses	Research and Development Expenses Research and development expenses consist of compensation costs, employee benefit costs, costs for contract manufacturing organizations (“CMOs”), costs for contract research organizations (“CROs”), costs for sponsored research, consulting costs, costs for laboratory supplies, costs for product licenses, facility-related expenses and depreciation. All research and development costs are charged to research and development expenses as incurred and included within the statements of operations and comprehensive loss. Payments associated with licensing agreements to acquire exclusive licenses to develop, use, manufacture and commercialize products that have not reached technological feasibility and do not have alternate commercial use are also expensed as incurred. Payments made to third parties under these arrangements in advance of the performance of the related services by the third parties are recorded as prepaid expenses until the services are rendered.
Accrued Research and Development Expenses	Accrued Research and Development Expenses The Company has entered into various agreements with CMOs and CROs. The Company’s research and development accruals are estimated based on the level of services performed, progress of the studies, including the phase or completion of events, and contracted costs. The estimated costs of research and development provided, but not yet invoiced, are included in accrued liabilities on the balance sheet. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments made to CMOs and CROs under these arrangements in advance of the performance of the related services are recorded as prepaid expenses and other current assets until the services are rendered.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation arrangements with employees and non-employees in accordance with ASC 718, Stock Compensation.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method whereby deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are currently in effect unless such rate is expected to be different when the deferred item reverses. Valuation allowances are established where necessary to reduce deferred tax assets to the amounts expected to be realized. Deferred tax assets and liabilities are classified as noncurrent on the balance sheet. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that has a greater than 50% likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to unrecognized tax benefits in interest expense and other expense, respectively.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ equity that are excluded from net loss, primarily unrealized gains and losses from the Company’s marketable securities.
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share 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, stock options, restricted stock and restricted stock that is subject to repurchase at the original purchase price are considered to be potentially dilutive securities. The Company 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 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 common share is the same as basic net loss per common share for those periods.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) under its accounting standard codifications (“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 December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and improves consistent application of and simplifies GAAP for other areas of Topic 740 by clarifying existing guidance. For public business entities, this ASU is effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted. The Company adopted this ASU on January 1, 2021. The adoption did not result in a material impact on the Company’s financial statements and related disclosures. New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Codification Improvements to Topic 326, Financial Instruments—Credit Losses
Fair Value Measurement and Marketable Securities	The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows: Level 1—Observable inputs, such as quoted prices in active markets for identical assets or liabilities at the measurement date . Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities . Level 3—Unobservable inputs which reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model . In determining fair value, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value.
Early Exercise of Stock Options	Early Exercise of Stock Options
Share Based Compensation Forfeiture	The Company accounts for forfeitures as they occur.

Fair Value Measurement and Ma_2

Fair Value Measurement and Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured and Recognized at Fair Value	As of December 31, 2021, financial assets measured and recorded at fair value are as follows (in thousands): December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Assets U.S. government securities Level 1 $ 122,657 $ — $ (592 ) $ 122,065 Corporate bonds Level 2 76,628 8 (127 ) 76,509 Commercial paper Level 2 77,444 — (1 ) 77,443 Marketable securities 276,729 8 (720 ) 276,017 Money market funds ( 1) Level 1 91,825 — — 91,825 Total fair value of assets $ 368,554 $ 8 $ (720 ) $ 367,842 (1) Included in cash and cash equivalents on the balance sheet As of December 31, 2020, financial assets measured and recognized at fair value are as follows (in thousands): December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Assets U.S. government securities Level 1 $ 80,020 $ 10 $ — $ 80,030 Corporate bonds Level 2 72,573 11 (14 ) 72,570 Commercial paper Level 2 63,948 — — 63,948 Marketable securities 216,541 21 (14 ) 216,548 Money market funds ( 1) Level 1 67,065 — — 67,065 Total fair value of assets $ 283,606 $ 21 $ (14 ) $ 283,613 (1) Included in cash and cash equivalents on the balance sheet

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Summary of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): Useful Life As of December 31, (In Years) 2021 2020 Laboratory equipment 5 $ 6,440 $ 4,793 Computer equipment 3 117 117 Software 3 204 118 Leasehold improvements Shorter of useful life or lease term 3,133 2,716 Furniture and fixtures 5 466 421 Total property and equipment 10,360 8,165 Less: Accumulated depreciation and amortization (5,597 ) (3,894 ) Property and equipment, net $ 4,763 $ 4,271
Summary of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): As of December 31, 2021 2020 Accrued research and development expenses $ 7,864 $ 5,259 Accrued salaries and benefits 3,971 2,685 Legal and professional fees 485 543 Other — 29 Accrued liabilities $ 12,320 $ 8,516

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Schedule of Maturities of Operating Lease Liabilities	The maturities of operating lease liabilities as of December 31, 2021 are as follows (in thousands): As of December 31, 2021 Operating Leases 2022 $ 1,982 2023 2,036 2024 1,647 Total lease payments 5,665 Less: Interest (484 ) Present value of lease liabilities $ 5,181 Amounts recognized on the balance sheet Current lease liabilities $ 1,699 Long-term lease liabilities 3,482 Total lease liabilities $ 5,181

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of Provision for Income Taxes	The provision for income taxes differs from the amount expected by applying the federal statutory rate to the loss before taxes as follows: Year Ended December 31, 2021 2020 2019 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % State income taxes 0.7 % (1.9 %) 7.0 % Change in valuation allowance (25.2 %) (21.5 %) (31.4 %) Research tax credits 3.8 % 2.7 % 3.6 % Other permanent differences (0.3 %) (0.3 %) (0.4 %) Change in fair value of redeemable convertible preferred stock liability 0.0 % 0.0 % 0.2 % Provision for income taxes 0.0 % 0.0 % 0.0 %
Schedule of Tax Effects of Temporary Differences and Carryforwards of Deferred Tax Assets	The tax effects of temporary differences and carryforwards of the deferred As of December 31, 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 27,324 $ 13,418 Research and development credit carryforwards 5,939 3,813 Lease liability 1,097 1,420 Intangible assets 1,179 1,274 Stock-based compensation 1,725 705 Accruals and reserves 882 505 Deferred revenue 12,575 17,332 Gross deferred tax assets 50,721 38,467 Less: Valuation allowance (49,575 ) (36,879 ) Deferred tax assets, net of valuation allowance 1,146 1,588 Deferred tax liabilities: Right-of-use assets (825 ) (1,100 ) Property and equipment (321 ) (488 ) Net deferred tax assets $ — $ —
Summary of Activity Related to Company?s Unrecognized Tax Benefits	The following table summarizes the activity related to the Company’s unrecognized tax benefits (in thousands). Balance as of January 1, 2020 $ 746 Increase related to prior year tax positions 2 Increase related to current year tax positions 153 Balance as of December 31, 2020 $ 901 Increase related to prior year tax positions 73 Increase related to current year tax positions 330 Balance as of December 31, 2021 $ 1,304

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2021
Stockholders Equity Note [Abstract]
Schedule of Number of Common Stock Reserved for Future Issuance	The Company had reserved common stock for future issuance as follows: As of December 31, 2021 2020 Exercise of outstanding options under the 2015 and 2019 Plans 3,620,666 2,591,456 Issuance of common stock options under the 2019 Plan 922,826 975,135 Issuance of common stock options under the Employee Stock Purchase Plan 602,935 357,600 Total 5,146,427 3,924,191

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Expense	Total stock-based compensation expense recorded related to awards granted to employees and non-employees was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Research and development $ 3,492 $ 1,234 $ 956 General and administrative 4,745 2,375 1,212 Total stock-based compensation expense $ 8,237 $ 3,609 $ 2,168
Summary of Activity under Plans	Activity under the Company’s 2015 and 2019 Plans is set forth below: Outstanding Options Shares available for Grant Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Balance, January 1, 2021 975,135 2,591,456 $ 7.27 8.36 $ 15.70 Additional shares authorized 1,181,488 — Options granted (1,560,425 ) 1,560,425 $ 20.52 Options exercised — (211,900 ) $ 7.13 Options repurchased — — Options canceled 326,628 (319,315 ) $ 14.33 Balance, December 31, 2021 922,826 3,620,666 $ 12.36 7.92 $ 41.40 Exercisable as of December 31, 2021 1,498,708 $ 6.58 6.60 $ 25.70 Vested and expected to vest as of December 31, 2021 3,620,666 $ 12.36 7.92 $ 41.40
Assumptions Used to Calculate Fair Values of Options	The fair values of options were calculated using the assumptions set forth below: Year Ended December 31, 2021 2020 2019 Expected term 5.5 - 6.1 years 5.5 - 6.1 years 5.4 - 6.1 years Expected volatility 90.0% - 103.6% 84.9 % - 98.3% 77.2% - 85.5% Risk-free interest rate 0.6% - 1.4% 0.3% - 1.5% 1.4% - 2.5 % Dividend yield 0% 0% 0%
Summary of Restricted Stock Activity	Restricted stock activity was as follows: Number of Shares Underlying Outstanding Restricted Stock Awards Weighted Average Grant Date Fair Value Unvested, December 31, 2020 14,625 $ 0.82 Vested (7,312 ) $ 0.82 Repurchased (7,313 ) $ 0.82 Unvested, December 31, 2021 —

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue From Contract With Customer [Abstract]
Summary of Revenue Disaggregated by Research Program	The following table presents revenue disaggregated by research program (in thousands): Year Ended December 31, 2021 2020 MAT2A $ 7,230 $ 6,048 Pol Theta 12,894 7,917 WRN 7,817 5,573 Total collaboration revenue $ 27,941 $ 19,538
Summary of Changes in Contact Liabilities	The following table presents the significant changes in the balance of contract liabilities during the year ended December 31, 2021 Contract liabilities Balance as of December 31, 2020 $ 83,773 Reclassification to revenue, as the result of performance obligations satisfied (27,941 ) Cash received for cost reimbursement 3,414 Increase in accounts receivable 986 Balance as of December 31, 2021 $ 60,232
Summary of Transaction Price Allocated to Remaining Performance Obligations	The following table presents the transaction price allocated to the remaining performance obligations as of December 31, 2021 Performance Obligations Allocation of Transaction Price MAT2A R&D Services $ 9,486 Pol Theta R&D Services 13,751 WRN R&D Services 20,829 The Option 17,680 MAT2A Supply 2,411 Total transaction price allocated to the remaining performance obligations $ 64,157

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2021
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 (in thousands, except share and per share data): Year Ended December 31, 2021 2020 2019 Numerator: Net loss attributable to common stockholders $ (49,762 ) $ (34,495 ) $ (41,975 ) Denominator: Weighted-average shares outstanding 35,262,987 24,783,287 12,669,367 Less: weighted-average shares of restricted stock that are subject to repurchase (10,544 ) (61,512 ) (172,410 ) Weighted-average shares used in computing net loss per share attributable to common stock, basic and diluted 35,252,443 24,721,775 12,496,957 Net loss per share attributable to common stockholders, basic and diluted $ (1.41 ) $ (1.40 ) $ (3.36 )
Schedule of Outstanding Shares of Potentially Dilutive Securities Excluded From the Computation of Diluted Net Loss Per Share	The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been antidilutive: As of December 31, 2021 2020 2019 Options to purchase common stock 3,620,666 2,591,456 1,962,332 Restricted stock — 14,625 14,625 Restricted stock acquired upon early exercise of stock options — 14,460 84,964 Total 3,620,666 2,620,541 2,061,921

Organization - Additional Infor

Organization - Additional Information (Details) - USD ($)	Jul. 12, 2021	Jan. 20, 2021	Aug. 12, 2020	Aug. 03, 2020	Jul. 22, 2020	Jun. 22, 2020	May 28, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Subsidiary Sale Of Stock [Line Items]
Proceeds from issuance of common stock upon public offering, net of issuance costs								$ 85,990,000	$ 100,664,000	$ 50,321,000
Accumulated deficit								176,748,000	$ 126,986,000
Cash, cash equivalents and marketable securities								368,100,000
Common Stock
Subsidiary Sale Of Stock [Line Items]
Conversion of redeemable convertible preferred stock into common stock, shares										13,139,794
Jefferies LLC | January 2021 Sales Agreement
Subsidiary Sale Of Stock [Line Items]
Common stock remained available to be sold								$ 73,800,000
IPO
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares							5,750,000
Common stock, price per share							$ 10
Conversion of redeemable convertible preferred stock into common stock, shares							13,139,794
Proceeds from issuance of common stock in initial public offering, net of issuance costs							$ 50,200,000
Underwriting discounts and commissions							4,000,000
Offering costs							$ 3,300,000
IPO | Common Stock
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares										5,750,000
Overallotment Option
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares	695,652				500,000		750,000
Follow-on Public Offering
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares	5,333,333					6,666,667
Common stock price per share	$ 17.25					$ 15
Gross proceeds from issuance common stock					$ 7,500,000	$ 100,000,000
Proceeds from issuance of common stock upon public offering, net of issuance costs	$ 86,000,000				$ 100,700,000
Follow-on Public Offering | Common Stock
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares								5,333,333	7,166,667
Private Placement | Common Stock
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares									1,333,333
Private Placement | Glaxo Group Limited
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares				1,333,333
Common stock price per share				$ 15
Proceeds from issuance of common stock upon public offering, net of issuance costs				$ 20,000,000
At The Market Offering | Common Stock
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares								3,407,872	410,896
At The Market Offering | Jefferies LLC | August 2020 Sales Agreement | Common Stock | Maximum
Subsidiary Sale Of Stock [Line Items]
Sale of common stock aggregate offering price			$ 50,000,000
At The Market Offering | Jefferies LLC | January 2021 Sales Agreement | Common Stock | Maximum
Subsidiary Sale Of Stock [Line Items]
Sale of common stock aggregate offering price		$ 90,000,000
At The Market Offering | Jefferies LLC | August 2020 Sales Agreement and January 2021 Sales Agreement | Common Stock
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock, net of issuance costs, shares								3,407,872
Proceeds from issuance of common stock upon public offering, net of issuance costs								$ 57,300,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)Segment	Dec. 31, 2020USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of operating segments	1
Number of reportable segments	1
Impairment of long-lived assets | $	$ 0	$ 0
ASU 2019-12
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 1, 2021
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
2019 Equity Incentive Plan
Summary Of Significant Accounting Policies [Line Items]
Term of options	10 years
Vesting period of options	4 years
2019 Equity Incentive Plan | Cliff Vesting
Summary Of Significant Accounting Policies [Line Items]
Vesting period of options	1 year
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of the assets	3 years
Recognized income tax positions measured at percentage of likelihood of realization	50.00%
Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of the assets	5 years

Fair Value Measurement and Ma_3

Fair Value Measurement and Marketable Securities - Schedule of Financial Assets Measured and Recognized at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	$ 276,729	$ 216,541
Marketable securities, gross unrealized gains	8	21
Marketable securities, gross unrealized losses	(720)	(14)
Marketable securities, estimated fair value	276,017	216,548
Amortized Cost	368,554	283,606
Estimated Fair Value	367,842	283,613
U.S. Government Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	122,657	80,020
Marketable securities, gross unrealized gains	0	10
Marketable securities, gross unrealized losses	(592)	0
Marketable securities, estimated fair value	122,065	80,030
Corporate Bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	76,628	72,573
Marketable securities, gross unrealized gains	8	11
Marketable securities, gross unrealized losses	(127)	(14)
Marketable securities, estimated fair value	76,509	72,570
Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, amortized cost	77,444	63,948
Marketable securities, gross unrealized gains	0	0
Marketable securities, gross unrealized losses	(1)	0
Marketable securities, estimated fair value	77,443	63,948
Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds, amortized Cost	91,825	67,065
Money market funds, estimated Fair Value	$ 91,825	$ 67,065

Fair Value Measurement and Ma_4

Fair Value Measurement and Marketable Securities - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial liabilities recognized at fair value	$ 0	$ 0
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities remaining maturity period	2 years	1 year

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Total property and equipment	$ 10,360	$ 8,165
Less: Accumulated depreciation and amortization	(5,597)	(3,894)
Property and equipment, net	4,763	4,271
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 6,440	4,793
Property and equipment net, useful life	5 years
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 117	117
Property and equipment net, useful life	3 years
Software
Property Plant And Equipment [Line Items]
Total property and equipment	$ 204	118
Property and equipment net, useful life	3 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	$ 3,133	2,716
Property and equipment net, useful life	Shorter of useful life or lease term
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	$ 466	$ 421
Property and equipment net, useful life	5 years

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Depreciation and amortization expense	$ 1.7	$ 1.4	$ 1.2

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued research and development expenses	$ 7,864	$ 5,259
Accrued salaries and benefits	3,971	2,685
Legal and professional fees	485	543
Other	0	29
Accrued liabilities	$ 12,320	$ 8,516

Operating Leases - Additional I

Operating Leases - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Leased Assets [Line Items]
Right-of-use assets	$ 3,898	$ 5,205
Operating lease liability	5,181
Operating lease cost	1,700	1,500	$ 1,500
Cash paid included in operating lease liabilities included in cash flow from operating activities	$ 1,900	$ 1,700	$ 1,700
South San Francisco, California
Operating Leased Assets [Line Items]
Operating lease, remaining lease term	2 years 7 months 6 days
Operating lease, discount rate	7.00%
Operating lease option to extend	true
Operating lease renewal term	2 years
South San Francisco, California | Second Amendment
Operating Leased Assets [Line Items]
Operating lease, discount rate	6.00%
South San Francisco, California | Lease Agreement | Laboratory and Office Facilities
Operating Leased Assets [Line Items]
Lease expiration date	Jul. 31, 2024
South San Francisco | Laboratory and Office Facilities | Second Amendment
Operating Leased Assets [Line Items]
Right-of-use assets	$ 1,200
Operating lease liability	$ 1,200
Operating lease commencement month and year	2020-08

Operating Leases - Schedule of

Operating Leases - Schedule of Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
2022	$ 1,982
2023	2,036
2024	1,647
Total lease payments	5,665
Less: Interest	(484)
Operating lease liability	5,181
Current lease liabilities	1,699	$ 1,540
Long-term lease liabilities	3,482	$ 5,183
Total lease liabilities	$ 5,181

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Line Items]
Provision for income taxes	$ 0	$ 0	$ 0
Deferred tax assets, net operating loss carryforwards	27,324,000	13,418,000
Research and development credit carryforwards	5,939,000	3,813,000
Unrecognized tax benefits	1,304,000	$ 901,000	$ 746,000
Federal Income Tax
Income Tax Disclosure [Line Items]
Deferred tax assets, net operating loss carryforwards	101,600,000
Deferred tax assets, operating loss carryforwards subject to expire	$ 11,600,000
Tax credit carry forward expiration year	2037
Deferred tax assets, operating loss carryforwards subject to do not expire	$ 90,000,000
Research and development credit carryforwards	4,200,000
California State Income Tax
Income Tax Disclosure [Line Items]
Deferred tax assets, net operating loss carryforwards	85,300,000
Deferred tax assets, operating loss carryforwards subject to expire	$ 85,300,000
Tax credit carry forward expiration year	2036
Research and development credit carryforwards	$ 3,700,000

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Income Taxes (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21.00%	21.00%	21.00%
State income taxes	0.70%	(1.90%)	7.00%
Change in valuation allowance	(25.20%)	(21.50%)	(31.40%)
Research tax credits	3.80%	2.70%	3.60%
Other permanent differences	(0.30%)	(0.30%)	(0.40%)
Change in fair value of redeemable convertible preferred stock liability	0.00%	0.00%	0.20%
Provision for income taxes	0.00%	0.00%	0.00%

Income Taxes - Schedule of Tax

Income Taxes - Schedule of Tax Effects of Temporary Differences and Carryforwards of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 27,324	$ 13,418
Research and development credit carryforwards	5,939	3,813
Lease liability	1,097	1,420
Intangible assets	1,179	1,274
Stock-based compensation	1,725	705
Accruals and reserves	882	505
Deferred revenue	12,575	17,332
Gross deferred tax assets	50,721	38,467
Less: Valuation allowance	(49,575)	(36,879)
Deferred tax assets, net of valuation allowance	1,146	1,588
Deferred tax liabilities:
Right-of-use assets	(825)	(1,100)
Property and equipment	(321)	(488)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Summary of Activ

Income Taxes - Summary of Activity Related to Company's Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Balance	$ 901	$ 746
Increase related to prior year tax positions	73	2
Increase related to current year tax positions	330	153
Balance	$ 1,304	$ 901

Common Stock - Additional Infor

Common Stock - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021USD ($)Vote$ / sharesshares	Dec. 31, 2020$ / sharesshares
Stockholders Equity Note [Abstract]
Common stock, shares authorized | shares	300,000,000	300,000,000
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001
Common stock, voting rights	Each share of common stock is entitled to one vote.
Number of common stock voting rights held per share | Vote	1
Common stock, dividends declared | $	$ 0

Common Stock - Schedule of Numb

Common Stock - Schedule of Number of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Number of common stock reserved for future issuance	5,146,427	3,924,191
Exercise of Outstanding Options | 2015 and 2019 Plans
Class Of Stock [Line Items]
Number of common stock reserved for future issuance	3,620,666	2,591,456
Issuance of Common Stock Options | 2019 Plan
Class Of Stock [Line Items]
Number of common stock reserved for future issuance	922,826	975,135
Issuance of Common Stock Options | Employee Stock Purchase Plan
Class Of Stock [Line Items]
Number of common stock reserved for future issuance	602,935	357,600

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, initially reserved for issuance	5,146,427	3,924,191
Stock-based compensation expense	$ 8,237,000	$ 3,609,000	$ 2,168,000
Weighted-average grant-date fair value of options granted	$ 16.09	$ 6.16
Aggregate intrinsic value of options exercised	$ 3,500,000	$ 1,700,000
Total unrecognized stock-based compensation expense for stock options	$ 22,200,000
Total unrecognized stock-based compensation expense, weighted-average period of recognition	2 years 7 months 9 days
Common stock repurchased	0	10,518
Estimated dividend yield	0.00%	0.00%	0.00%
Issuance of Common Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to repurchase	0	14,460
Other Current Liabilities and Other Non-Current Liabilities
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate exercise prices of early exercised shares	$ 0
Maximum | Other Current Liabilities and Other Non-Current Liabilities
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate exercise prices of early exercised shares		$ 100,000
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	0
Total fair value of stock vested	$ 100,000	$ 0
Shares of restricted stock	0	14,625
Aggregate purchase price of unvested restricted stock subject to repurchase	$ 0
Restricted Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate purchase price of unvested restricted stock subject to repurchase		$ 100,000
2019 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Term of options	10 years
Vesting period of options	4 years
2019 Equity Incentive Plan | Cliff Vesting
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of options	1 year
2019 Equity Incentive Plan | 10% Stockholder
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Term of options	5 years
2019 Equity Incentive Plan | Incentive Stock Options and Nonqualified Stock Options | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair value of the shares on the grant date	100.00%
2019 Equity Incentive Plan | Incentive Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of voting power of all classes of stock	10.00%
2019 Equity Incentive Plan | Incentive Stock Options | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair value of the shares on the grant date	110.00%
2019 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, initially reserved for issuance	195,000
Stock-based compensation expense	$ 300,000	$ 200,000
Maximum offering period under ESPP	27 months
Maximum eligible rate of compensation	15.00%
2019 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of the fair value of common stock	85.00%
Maximum number of shares purchasable	4,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 8,237	$ 3,609	$ 2,168
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	3,492	1,234	956
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 4,745	$ 2,375	$ 1,212

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity under Plans (Details) - 2015 and 2019 Plans - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding Options, Shares available for Grant, Beginning balance	975,135
Outstanding Options, Shares available for Grant, Additional shares authorized	1,181,488
Outstanding Options, Shares available for Grant, Options granted	(1,560,425)
Outstanding Options, Shares available for Grant, Options canceled	326,628
Outstanding Options, Shares available for Grant, Ending balance	922,826	975,135
Outstanding Options, Shares, Beginning balance	2,591,456
Outstanding Options, Shares, Options granted	1,560,425
Outstanding Options, Shares, Options exercised	(211,900)
Outstanding Options, Shares, Options canceled	(319,315)
Outstanding Options, Shares, Ending balance	3,620,666	2,591,456
Outstanding Options, Shares, Exercisable	1,498,708
Outstanding Options, Shares, Vested and expected to vest	3,620,666
Outstanding Options, Weighted-Average Exercise Price, Beginning balance	$ 7.27
Outstanding Options, Weighted-Average Exercise Price, Options granted	20.52
Outstanding Options, Weighted-Average Exercise Price, Options exercised	7.13
Outstanding Options, Weighted-Average Exercise Price, Options canceled	14.33
Outstanding Options, Weighted-Average Exercise Price, Ending balance	12.36	$ 7.27
Outstanding Options, Weighted-Average Exercise Price, Exercisable	6.58
Outstanding Options, Weighted-Average Exercise Price, Vested and expected to vest	$ 12.36
Outstanding Options, Weighted Average Remaining Contractual Term (Years)	7 years 11 months 1 day	8 years 4 months 9 days
Outstanding Options, Weighted Average Remaining Contractual Term (Years), Exercisable	6 years 7 months 6 days
Outstanding Options, Weighted Average Remaining Contractual Term (Years), Vested and expected to vest	7 years 11 months 1 day
Outstanding Options, Aggregate Intrinsic Value	$ 41,400	$ 15,700
Outstanding Options, Aggregate Intrinsic Value, Exercisable	25,700
Outstanding Options, Aggregate Intrinsic Value, Vested and expected to vest	$ 41,400

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used to Calculate Fair Values of Options (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	90.00%	84.90%	77.20%
Expected volatility, maximum	103.60%	98.30%	85.50%
Risk-free interest rate, minimum	0.60%	0.30%	1.40%
Risk-free interest rate, maximum	1.40%	1.50%	2.50%
Dividend yield	0.00%	0.00%	0.00%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	5 years 6 months	5 years 6 months	5 years 4 months 24 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares Underlying Outstanding Restricted Stock Awards, Unvested, December 31, 2020	14,625
Number of Shares Underlying Outstanding Restricted Stock Awards, Vested	(7,312)
Number of Shares Underlying Outstanding Restricted Stock Awards, Repurchased	(7,313)
Number of Shares Underlying Outstanding Restricted Stock Awards, Unvested, December 31, 2021	0
Weighted Average Grant Date Fair Value, Unvested, December 31, 2020 | $ / shares	$ 0.82
Weighted Average Grant Date Fair Value, Vested | $ / shares	0.82
Weighted Average Grant Date Fair Value, Repurchased | $ / shares	$ 0.82

Significant Agreements - Additi

Significant Agreements - Additional Information (Details) - USD ($)	Jul. 31, 2020	Jun. 30, 2020	Sep. 30, 2018
Maximum | License Agreement | Novartis International Pharmaceuticals Limited
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contingent development and sales milestone payments			$ 29,000,000
GSK Collaboration Agreement | GSK
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment	$ 100,000,000
Number of days of notice period for terminating agreement		90 days
MAT2A Program
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development costs sharing percentage		20.00%
Percentage of profit share		50.00%
MAT2A Program | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development and regulatory milestone payment eligible to receive		$ 465,000,000
Commercial milestone payment eligible to receive		475,000,000
MAT2A Program | GSK
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Option exercise payment agreed to be received		$ 50,000,000
Development costs sharing percentage		80.00%
Pol Theta Program | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development and regulatory milestone payment eligible to receive		$ 485,000,000
Commercial milestone payment eligible to receive		$ 475,000,000
WRN Program
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development costs sharing percentage		20.00%
Percentage of profit share		50.00%
WRN Program | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Commercial milestone payment eligible to receive		$ 475,000,000
Development milestone payment eligible to receive		$ 485,000,000
WRN Program | GSK
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development costs sharing percentage		80.00%

Revenue Recognition - Summary o

Revenue Recognition - Summary of Revenue Disaggregated by Research Program (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Total collaboration revenue	$ 27,941	$ 19,538
MAT2A Program
Disaggregation Of Revenue [Line Items]
Total collaboration revenue	7,230	6,048
Pol Theta Program
Disaggregation Of Revenue [Line Items]
Total collaboration revenue	12,894	7,917
WRN Program
Disaggregation Of Revenue [Line Items]
Total collaboration revenue	$ 7,817	$ 5,573

Revenue Recognition - Contract

Revenue Recognition - Contract Balance - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Contract liabilities	$ 60,232	$ 83,773
GSK Collaboration Agreement
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Accounts receivable	1,100	1,900
Contract liabilities	$ 60,200	$ 83,800

Revenue Recognition - Summary_2

Revenue Recognition - Summary of Changes in Contact Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Contract With Customer Asset And Liability [Abstract]
Balance as of December 31, 2020	$ 83,773
Reclassification to revenue, as the result of performance obligations satisfied	(27,941)
Cash received for cost reimbursement	3,414
Increase in accounts receivable	986
Balance as of December 31, 2021	$ 60,232

Revenue Recognition - Performan

Revenue Recognition - Performance Obligations - Additional Information (Details)	Jul. 27, 2020obligation	Dec. 31, 2021Option
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Reimbursement period of costs incurred for quarter ended		75 days
Number of additional customer options | Option		2
GSK
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Reimbursement period of costs incurred for quarter ended		75 days
GSK Collaboration Agreement
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Number of performance obligations | obligation	6
Pol Theta Program
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Reimbursement period of costs incurred for quarter ended		90 days
WRN Program
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Reimbursement period of costs incurred for quarter ended		75 days
Determination period of costs incurred		75 days

Revenue Recognition - Summary_3

Revenue Recognition - Summary of Transaction Price Allocated to Remaining Performance Obligations (Details) $ in Thousands	Dec. 31, 2021USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 64,157
MAT2A R&D Services
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	9,486
Pol Theta R&D Services
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	13,751
WRN R&D Services
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	20,829
The Option
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	17,680
MAT2A Supply
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 2,411

Net Loss Per Share Attributab_3

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	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss	$ (49,762)	$ (34,495)	$ (41,975)
Denominator:
Weighted-average shares outstanding	35,262,987	24,783,287	12,669,367
Less: weighted-average shares of restricted stock that are subject to repurchase	(10,544)	(61,512)	(172,410)
Weighted-average shares used in computing net loss per share attributable to common stock, basic and diluted	35,252,443	24,721,775	12,496,957
Net loss per share attributable to common stockholders, basic and diluted	$ (1.41)	$ (1.40)	$ (3.36)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Schedule of Outstanding Shares of Potentially Dilutive Securities Excluded From the Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	3,620,666	2,620,541	2,061,921
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	3,620,666	2,591,456	1,962,332
Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	0	14,625	14,625
Restricted Stock Acquired upon Early Exercise of Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	0	14,460	84,964

401(k) Retirement Savings Plan

401(k) Retirement Savings Plan - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Percentage of maximum annual contribution per employee	90.00%
Matching contributions amount	$ 0.2	$ 0.2	$ 0.2
Defined contribution plan, plan name extensible description	401(k) plan	401(k) plan	401(k) plan
Defined Contribution Plan, Sponsor Location [Extensible Enumeration]	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember	us-gaap:DomesticPlanMember
Defined Contribution Plan, Tax Status [Extensible List]	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) $ / shares in Units, $ in Thousands	Jan. 28, 2022GBP (£)	Jan. 31, 2022USD ($)$ / sharesshares	Dec. 31, 2021USD ($)shares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)
Subsequent Event [Line Items]
Proceeds from issuance of common stock upon public offering, net of issuance costs | $			$ 85,990	$ 100,664	$ 50,321
Subsequent Event
Subsequent Event [Line Items]
Payment of one-time option exercise fee | £	£ 250,000
Payments for achievement of specific development and regulatory approval events | £	£ 19,500,000
At The Market Offering | Common Stock
Subsequent Event [Line Items]
Issuance of common stock, net of issuance costs, shares | shares			3,407,872	410,896
At The Market Offering | Subsequent Event | Jefferies LLC | January 2021 Sales Agreement | Common Stock
Subsequent Event [Line Items]
Issuance of common stock, net of issuance costs, shares | shares		2,173
Proceeds from issuance of common stock upon public offering, net of issuance costs | $		$ 50
Weighted average sales price | $ / shares		$ 24.01