Unity Biotechnology (UBX) 10-Q 10 May 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	May 05, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Trading Symbol	UBX
Entity Registrant Name	Unity Biotechnology, Inc.
Entity Central Index Key	0001463361
Current Fiscal Year End Date	--12-31
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		69,168,939
Entity Shell Company	false
Entity File Number	001-38470
Entity Tax Identification Number	26-4726035
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	285 East Grand Ave.
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	416-1192
Title of 12(b) Security	Common Stock, par value $0.0001
Security Exchange Name	NASDAQ

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	[1]
Current assets:
Cash and cash equivalents	$ 16,446	$ 32,905
Short-term marketable securities	62,717	55,170
Prepaid expenses and other current assets	1,770	1,879
Restricted cash	550	550
Total current assets	81,483	90,504
Property and equipment, net	9,308	9,942
Operating lease right-of-use assets	20,706	21,286
Long-term marketable securities	0	1,993
Long-term restricted cash	896	896
Other long-term assets	76	91
Total assets	112,469	124,712
Current liabilities:
Accounts payable	3,323	1,985
Accrued compensation	2,837	4,028
Accrued and other current liabilities	6,692	6,370
Deferred revenue	216	216
Derivative liability related to debt	0	963
Current portion of long-term debt	4,837	3,055
Total current liabilities	17,905	16,617
Operating lease liability, net of current portion	29,339	30,094
Long-term debt, net	14,534	18,409
Other long-term liabilities	0	23
Total liabilities	61,778	65,143
Commitments and contingencies (Note 6)
Stockholders’ equity:
Convertible preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.0001 par value; 300,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 69,148,106 and 62,991,906 shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively	7	6
Additional paid-in capital	469,799	459,631
Accumulated other comprehensive loss	(176)	(44)
Accumulated deficit	(418,939)	(400,024)
Total stockholders’ equity	50,691	59,569
Total liabilities and stockholders’ equity	$ 112,469	$ 124,712
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	10,000,000	10,000,000
Convertible preferred stock, shares issued	0	0
Convertible 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	69,148,106	62,991,906
Common stock, shares outstanding	69,148,106	62,991,906

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses:
Research and development	$ 12,461	$ 8,717
General and administrative	5,806	6,226
Total operating expenses	18,267	14,943
Loss from operations	(18,267)	(14,943)
Interest income	29	36
Interest expense	(808)	(775)
Other income (expense), net	131	(74)
Net loss	(18,915)	(15,756)
Other comprehensive (loss) gain
Unrealized (loss) gain on marketable debt securities	(132)	10
Comprehensive loss	$ (19,047)	$ (15,746)
Net loss per share, basic and diluted	$ (0.28)	$ (0.29)
Weighted-average number of shares used in computing net loss per share, basic and diluted	67,528,552	54,169,349

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total		At The Market Equity Offering Program	Equity Purchase AgreementLincoln Park Capital Fund LLC	Loan AgreementHercules Capital	Common Stock	Common StockAt The Market Equity Offering Program	Common StockEquity Purchase AgreementLincoln Park Capital Fund LLC	Common StockLoan AgreementHercules Capital	Additional Paid-In Capital	Additional Paid-In CapitalAt The Market Equity Offering Program	Additional Paid-In CapitalEquity Purchase AgreementLincoln Park Capital Fund LLC	Additional Paid-In CapitalLoan AgreementHercules Capital	Related Party Promissory Notes for Purchase of Common Stock	Employee Promissory Notes for Purchase of Common Stock	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2020	$ 82,880					$ 5				$ 422,379				$ (210)		$ 5	$ (339,299)
Beginning balance, (in shares) at Dec. 31, 2020						53,253,213
Issuance of common stock, net of issuance costs			$ 8,892								$ 8,892
Issuance of common stock (in shares)							1,220,629
Vesting of restricted stock units, (in shares)						88,218
Issuance of common stock upon exercise of stock options	1,183									1,183
Issuance of common stock upon exercise of stock options (in shares)						259,019
Repurchase of early exercised shares, (in shares)						(33,370)
Stock-based compensation	2,744									2,744
Reclass of promissory notes for purchase ofcommon stock														$ 210	$ (210)
Unrealized (loss) gain on marketable debt securities	10															10
Net loss	(15,756)																(15,756)
Ending balance at Mar. 31, 2021	79,953					$ 5				435,198					$ (210)	15	(355,055)
Ending balance, (in shares) at Mar. 31, 2021						54,787,709
Beginning balance at Dec. 31, 2021	$ 59,569	[1]				$ 6				459,631						(44)	(400,024)
Beginning balance, (in shares) at Dec. 31, 2021	62,991,906					62,991,906
Issuance of common stock, net of issuance costs			$ 3,420	$ 910	$ 3,179				$ 1		$ 3,420	$ 910	$ 3,178
Issuance of common stock (in shares)				900,000			2,325,000	900,000	2,627,612
Vesting of restricted stock units, (in shares)						303,588
Stock-based compensation	$ 2,660									2,660
Unrealized (loss) gain on marketable debt securities	(132)															(132)
Net loss	(18,915)																(18,915)
Ending balance at Mar. 31, 2022	$ 50,691					$ 7				$ 469,799						$ (176)	$ (418,939)
Ending balance, (in shares) at Mar. 31, 2022	69,148,106					69,148,106
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Operating activities
Net loss	$ (18,915)	$ (15,756)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	627	757
Amortization of debt issuance costs	322	191
Debt extinguishment gain upon conversion to equity	(199)	0
Net accretion and amortization of premium and discounts on marketable securities	131	290
Stock-based compensation	2,660	2,744
Non-cash rent expense	(626)	(556)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	110	1,585
Other long-term assets	14	0
Accounts payable	1,345	(640)
Accrued compensation	(1,191)	(3,516)
Accrued liabilities and other current liabilities	774	(190)
Other long-term liabilities	(24)	0
Net cash used in operating activities	(14,972)	(15,091)
Investing activities
Purchase of marketable securities	(17,067)	(38,174)
Maturities of marketable securities	11,250	52,250
Purchase of property and equipment	0	(14)
Net cash provided by investing activities	(5,817)	14,062
Financing activities
Proceeds from issuance of common stock upon exercise of stock options, net of repurchases	0	1,172
Net cash provided by financing activities	4,330	10,064
Net increase (decrease) in cash, cash equivalents and restricted cash	(16,459)	9,035
Cash, cash equivalents and restricted cash at beginning of the period	34,351	19,253	$ 19,253
Cash, cash equivalents and restricted cash at end of the period	17,892	28,288	34,351
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest	518	584
Supplemental Disclosures of Non-Cash Investing and Financing Activities
Issuance of common stock in payment of debt	3,178	0
Property and equipment included in accounts payable and accrued liabilities	0	57
Cash and cash equivalents	16,446	26,842	$ 32,905	[1]
Restricted cash	1,446	1,446
ATM Offering Program
Financing activities
Proceeds from issuance of common stock, net of issuance costs	3,420	8,892
Lincoln Park Capital Fund
Financing activities
Proceeds from issuance of common stock, net of issuance costs	$ 910	$ 0
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Organization

Organization	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	1. Organization Description of Business Unity Biotechnology, Inc. (the “Company”) is a biotechnology company engaged in the research and development of therapeutics to slow, halt, or reverse diseases of aging. The Company devotes substantially all of its time and efforts to performing research and development, raising capital, and recruiting personnel. The Company’s headquarters are located in South San Francisco, California. The Company was incorporated in the State of Delaware in 2009. Liquidity In accordance with Accounting Standards Update (“ASU”) No. 2014-15, Disclosures of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40) The Company’s Condensed Financial Statements have been prepared on a going concern basis, which contemplates the continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. The Company has incurred operating losses and has an accumulated deficit as a result of ongoing efforts to develop drug product candidates, including conducting preclinical and clinical trials and providing general and administrative support for these operations. The Company had an accumulated deficit of $418.9 million and $400.0 million as of March 31, 2022 and December 31, 2021, respectively. The Company had net losses of $18.9 million and $15.8 million for the three months ended March 31, 2022 and 2021, respectively, and net cash used in operating activities of $15.0 million and $15.1 million for the three months ended March 31, 2022 and 2021, respectively. To date, none of the Company’s drug candidates have been approved for sale, and therefore, the Company has not generated any product revenue and does not expect positive cash flows from operations in the foreseeable future. The Company has financed its operations primarily through private placements of preferred stock and promissory notes, public equity issuances and more recently, from its ATM Offering Programs (as defined in Note 9), the Term Loan Facility (as defined in Note 7), and an Equity Purchase Agreement (as defined in Note 9) and will continue to be dependent upon equity and/or debt financing until the Company is able to generate positive cash flows from its operations. The Company had cash, cash equivalents, and marketable securities of $79.2 million as of March 31, 2022. As of May 10, 2022, the date of issuance of these Condensed Financial Statements, the Company expects that its cash and cash equivalents as of March 31, 2022 will not be sufficient to fund its current business plan including related operating expenses and capital expenditure requirements through at least 12 months from the date of issuance of these Condensed Financial Statements. These conditions raise substantial doubt about the Company’s ability to continue as a going concern. The Company plans to seek to address this condition by raising additional capital to finance its operations. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations. Although the Company has been successful in raising capital in the past, there is no assurance that it will be successful in obtaining such additional financing. Therefore, it is not considered probable, as defined in ASU No. 2014-15, that the Company’s plans to raise additional capital will alleviate the substantial doubt regarding its ability to continue as a going concern. Management expects operating losses to continue for the foreseeable future. As a result, the Company will need to raise additional capital. If sufficient funds on acceptable terms are not available when needed, the Company could be required to significantly reduce its operating expenses and delay, reduce the scope of, or eliminate one or more of its development programs. Failure to manage discretionary spending or raise additional financing, as needed, may adversely impact the Company’s ability to achieve its intended business objectives.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation These condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for interim reporting. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted. Accordingly, the unaudited condensed financial statements should be read in conjunction with the audited financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 filed with the SEC. Unaudited Condensed Financial Statements The accompanying financial information for the three months ended March 31, 2022 and 2021 are unaudited. The unaudited condensed financial statements have been prepared on the same basis as the annual audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position as of March 31, 2022 and its results of operations for the three months ended March 31, 2022 and 2021 and cash flows for the three months ended March 31, 2022 and 2021. The results for interim periods are not necessarily indicative of the results expected for the full fiscal year or any other periods. Use of Estimates The condensed financial statements have been prepared in accordance with GAAP, which requires management to make estimates and assumptions that affect the amounts and disclosures reported in the condensed financial statements and accompanying notes. The Company bases its estimates on historical experience and market-specific or other relevant assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company’s condensed balance sheets and the amount of expenses and income reported for each of the periods presented are affected by estimates and assumptions, which are used for, but are not limited to, determining the fair value of assets and liabilities, contingent consideration liability, the fair value of right-of-use assets and lease liabilities, derivative liabilities related to debt and stock-based compensation. Actual results could differ from such estimates or assumptions. Segments The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purposes of allocating resources. Restructuring The Company recognizes restructuring charges related to reorganization plans that have been committed to by management and when liabilities have been incurred. In connection with these activities, the Company records restructuring charges at fair value for a) contractual employee termination benefits when obligations are associated to services already rendered, rights to such benefits have vested, and payment of benefits is probable and can be reasonably estimated, and b) one-time employee termination benefits when management has committed to a plan of termination, the plan identifies the employees and their expected termination dates, the details of termination benefits are complete, it is unlikely changes to the plan will be made or the plan will be withdrawn and communication to such employees has occurred. One-time employee termination benefits are recognized in their entirety when communication has occurred, and future services are not required. Contract termination costs to be incurred over the remaining contract term without economic benefit are recorded in their entirety when the contract is canceled. The recognition of restructuring charges requires the Company to make certain judgments and estimates regarding the nature, timing and amount of costs associated with the planned reorganization plan. At the end of each reporting period, the Company evaluates the remaining accrued restructuring balances to ensure that no excess accruals are retained, and the utilization of the provisions are for their intended purpose in accordance with developed restructuring plans. Recently Issued Accounting Pronouncements Not Yet Adopted In October 2020, the FASB issued ASU 2020-10, Codification Improvements In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The Company determines the fair value of financial and non-financial assets and liabilities based on the assumptions that market participants would use in pricing the asset or liability in an orderly transaction between market participants at the measurement date. The identification of market participant assumptions provides a basis for determining what inputs are to be used for pricing each asset or liability. A fair value hierarchy has been established which gives precedence to fair value measurements calculated using observable inputs over those using unobservable inputs. This hierarchy prioritized the inputs into three broad levels as follows: • Level 1: Quoted prices in active markets for identical instruments • Level 2: Other significant observable inputs (including quoted prices in active markets for similar instruments) • Level 3: Significant unobservable inputs (including assumptions in determining the fair value of certain investments) The carrying amounts of financial instruments such as cash and cash equivalents, restricted cash, prepaid expenses and other current assets, accounts payable, accrued compensation, accrued and other current liabilities approximate the related fair values due to the short maturities of these instruments. As the long-term debt is subject to variable interest rates that are based on market rates which are regularly reset, considering level 2 inputs, the Company believes the carrying value of the long-term debt approximates its fair value. The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements were as follows (in thousands): March 31, 2022 Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 9,766 $ 9,766 $ — $ — U.S. treasuries 2,000 — 2,000 — Total cash equivalents 11,766 9,766 2,000 — Short-term marketable securities: U.S. treasuries 59,709 — 59,709 — U.S. government debt securities 3,008 — 3,008 — Total short-term marketable securities 62,717 — 62,717 — Total assets subject to fair value measurements on a recurring basis $ 74,483 $ 9,766 $ 64,717 $ — December 31, 2021 Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 21,421 $ 21,421 $ — $ — Total cash equivalents 21,421 21,421 — — Short-term marketable securities: U.S. treasuries 52,146 — 52,146 — U.S. government debt securities 3,024 — 3,024 — Total short-term marketable securities 55,170 — 55,170 — Long-term marketable securities: U.S. treasuries 1,993 — 1,993 — Total long-term marketable securities 1,993 — 1,993 — Total assets subject to fair value measurements on a recurring basis $ 78,584 $ 21,421 $ 57,163 $ — The Company estimates the fair value of its money market funds, U.S. and foreign commercial paper, U.S. and foreign corporate debt securities, U.S. treasuries, and U.S. government debt securities by taking into consideration valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads; benchmark securities; prepayment/default projections based on historical data; and other observable inputs. See Note 4, “Marketable Securities,” for further information regarding the carrying value of the Company's financial instruments. In December 2021, the Company recorded a derivative liability relating to an amendment to its loan and security agreement. It comprised of a redemption conversion feature which met the definition of a derivative instrument, which terms are included in the amended loan and security agreement. See Note 7, “Term Loan Facility”. The Company classified this instrument as a liability on the balance sheet because the feature was not clearly and closely related to its host instrument and met the definition of a derivative. The derivative liability was initially recorded at fair value upon issuance of the loan amendment and is being subsequently remeasured to fair value at each reporting date. Changes in the fair value of the derivative liability are recognized as a component of other income (expense), net in the statements of operations. The following table provides a reconciliation of the derivative liability related to debt measured at fair value on a recurring basis using significant unobservable inputs (Level 3) (in thousands): Derivative Liability related to Debt Conversion Feature ( 1) Balance at December 31, 2021 $ 963 Additions — Conversion (963 ) Change in fair value — Balance at March 31, 2022 $ — (1) Transfers into Level 3 during the year ended December 31, 2021 relate to the call option with Hercules Capital, Inc, where the lender can convert principal debt into common stock. Transfers out of Level 3 during the year relate to the conversions calls of this option made by Hercules Capital, Inc.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2022
Investments Debt And Equity Securities [Abstract]
Marketable Securities	4. Marketable Securities Marketable securities, which are classified as available-for-sale, consisted of the following as of March 31, 2022 (in thousands): Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds $ 9,766 $ — $ — $ 9,766 U.S. treasuries 2,000 — — 2,000 Total cash equivalents 11,766 — — 11,766 Short-term marketable securities: U.S. government debt securities 3,016 — (8 ) 3,008 U.S. treasuries 59,877 — (168 ) 59,709 Total short-term marketable securities 62,893 — (176 ) 62,717 Total $ 74,659 $ — $ (176 ) $ 74,483 Marketable securities, which are classified as available-for-sale, consisted of the following as of December 31, 2021 (in thousands): Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds $ 21,421 $ — $ — $ 21,421 Total cash equivalents 21,421 — — 21,421 Short-term marketable securities: U.S. government debt securities 3,026 — (2 ) 3,024 U.S. treasuries 52,186 — (40 ) 52,146 Total short-term marketable securities 55,212 — (42 ) 55,170 Long-term marketable securities U.S. treasuries 1,995 — (2 ) 1,993 Total long-term marketable securities 1,995 — (2 ) 1,993 Total $ 78,628 $ — $ (44 ) $ 78,584 At March 31, 2022, the remaining contractual maturities of available-for-sale securities were less than one year. There have been no significant realized gains or losses on available-for-sale securities for the periods presented. Available-for-sale debt securities that were in a continuous loss position but were not deemed to be other than temporarily impaired were immaterial at both March 31, 2022 and December 31, 2021. The Company does not intend to and believes it is not more likely than not that it will be required to sell these debt securities before their maturities. See Note 3, “Fair Value Measurements,” for further information regarding the fair value of the Company ’ s financial instruments.

License Revenue and Agreements

License Revenue and Agreements	3 Months Ended
	Mar. 31, 2022
Research And Development [Abstract]
License Revenue and Agreements	5. License Revenue and Agreements The Company has entered into license agreements with other pharmaceutical and biotechnology companies. The Company’s accounts receivable balances may contain billed and unbilled amounts from milestones and other contingent payments. The Company performs a regular review of its customers’ credit risk and payment histories, including payments made after period end. Historically, the Company has not experienced credit loss from its accounts receivable and, therefore, has not recorded a reserve for estimated credit losses as of March 31, 2022 and December 31, 2021. License Agreement with Jocasta Neuroscience, Inc. In December 2021, the Company signed a License Agreement with Jocasta Neuroscience, Inc. (“the Jocasta Agreement”) to exclusively license its rights in the α-Klotho asset for development and commercialization, and included a sublicense agreement under the original license agreement with the University of California, San Francisco. Under the Jocasta Agreement, the Company received a $5.0 million upfront cash payment from Jocasta Neuroscience, Inc. The Company may also receive additional payments based on development milestones, approval milestones, and sales-based royalties, per indication. The Jocasta agreement is recognized in accordance with ASC 606, Revenue from Contracts with Customers , and is classified under License Revenue. Promises that the Company concluded were distinct performance obligations in the License Agreement included: (1) the license of intellectual property and delivery of know-how, and (2) the transfer of licensed compounds and materials. In order to determine the transaction price, the Company evaluated all the payments to be received during the duration of the contract. Fixed consideration exists in the form of the upfront payment. Regulatory milestones and royalties were considered variable consideration. The estimated variable consideration is constrained until the Company determines it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur in future periods. Milestone payments are constrained and not included in the transaction price due to the uncertainties of research and development. The Company will re-evaluate 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. The Company determined that the initial transaction price consists of the upfront payment of $5.0 million. The allocation of the transaction price is performed based on standalone selling prices, which are based on estimated amounts that the Company would charge for a performance obligation if it were sold separately. The transaction price allocated to the license of intellectual property and delivery of know-how was recognized upon grant of license and delivery of know-how. The transaction price allocated the transfer of licensed compounds and materials, will be recognized over time as the materials are delivered. Consideration received in advance are recorded as deferred revenue and will be recognized as the performance obligations are satisfied. For the three months ended March 31, 2022 and 2021, the Company did not recognize any license revenue or any deferred revenue related to the Jocasta Agreement. The deferred revenue balance was $0.2 million as of March 31, 2022 and December 31, 2021. License Agreements with Research Institutions In May 2019, the Company entered into a license agreement with The Regents of the University of California on behalf its San Francisco campus (collectively, “UCSF”) which provides the Company the rights to certain patents and related know-how to make, use, sell, offer for sale and import certain products and practice certain methods for use in the development of human therapeutics, which excludes the provision of services to third parties for consideration of any kind. The license to the Company is subject to UCSF’s reserved rights under the licensed intellectual property for educational and non-commercial research purposes and a requirement to substantially manufacture any licensed products in the United States. The Company is obligated to use diligent efforts to develop and obtain regulatory approval for at least one product commercialized pursuant to the agreement, and must meet certain regulatory and development milestones. In June 2019, as part of this license agreement, the Company issued 120,000 shares of its common stock to UCSF. In addition, the Company is obligated to pay an annual license maintenance fee and may be obligated to make milestone payments or issue up to an additional 34,000 shares of its common stock upon the occurrence of specified development events, up to aggregate milestone payments of $ 13.6 million for each product licensed under the agreement, and upon commercialization, to make royalty payments in the low single digit percentages (subject to a specified minimum annual royalty) based on net sales of products commercialized pursuant to the agreement. None of these events had occurred and no milestone payments or royalty payments had been recognized as of March 31, 2022. The upfront issuance of 120,000 shares of the Company’s common stock was valued at $ 1.0 million and recorded as additional paid-in capital upon issuance in June 2019. In December 2021, the Company entered an agreement to exclusively license its rights in the α-Klotho asset to Jocasta Neuroscience, Inc. for development and commercialization. Under the license agreement, Jocasta Neuroscience, Inc. is, in addition to the payments due to the Company, required to make all payments due to UCSF from the Company under the UCSF License. See above, “License Agreement with Jocasta Neuroscience, Inc.” for additional information on the Jocasta Agreement. The Company has also entered into license agreements with various research institutions which have provided the Company with rights to patents, and in certain cases, research “know-how” and proprietary research tools to research, develop and commercialize drug candidates. In addition to upfront consideration paid to these various research institutions in either cash or shares of the Company’s common stock, the Company may be obligated to make milestone payments, payable in cash and/or the issuance of shares of the Company’s common stock upon achievement of certain specified clinical development and/or sales events. There was no contingent consideration liability considered to be a derivative associated with the potential issuance of common stock related to these license agreements at March 31, 2022 and December 31, 2021. To date, none of these events has occurred and no contingent consideration, milestone or royalty payments have been recognized. License and Compound Library and Option Agreement The Company is a party to three agreements, two active and one terminated, with Ascentage Pharma: (a) a compound library and option agreement executed in February 2016 granting the Company the right to identify and take licenses to research, develop, and seek and obtain marketing approval for library compounds for the treatment of indications outside of oncology (the “Library Agreement”), (b) an initial license agreement executed in February 2016 granting the Company rights to an initial Ascentage Pharma compound known as APG1252 (the “APG1252 License Agreement”), and (c) a second license agreement executed in January 2019 granting the Company rights to a second licensed compound (this second license agreement, the “Bcl License Agreement” and collectively with the Library Agreement and APG1252 License Agreement, the “Commercial Agreements”). On July 30, 2020, the Company notified Ascentage Pharma of its termination of the APG1252 License Agreement due to the Company’s decision to prioritize the progression of other compounds from Ascentage International’s library of Bcl-2 inhibitors, such as UBX1325, a Bcl-xL inhibitor. The Commercial Agreements referenced above include cash payments of up to $70.3 million as well as the equity payments of up to an aggregate of (a) 933,337 shares of common stock in the event there is only one licensed product, and (b) 1,333,338 shares of common stock in the event there are two or more licensed products, in each case to be issued As of March 31, 2022, pursuant to these agreements, the Company had issued 1,269,755 shares of common stock to Ascentage Pharma and 291,944 shares of common stock to the academic institution from whom Ascentage Pharma had previously licensed the technology. In May 2021, the Company initiated a Phase 2 year ended December 31, 2021 . The Company had previously issued 361,664 shares of its common stock with a value of $ 2.3 million to Ascentage Pharma as of December 31, 2020. The Commercial Agreements included contingent consideration in the form of additional issuances of shares of the Company’s common stock based on the achievement of the specified milestones. Upon the July 2020 termination of the license to APG1252, the Company determined that the contingency no longer applied and adjusted the fair value of the contingent consideration liability to zero. To date, no royalties were due from the sales of licensed products.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Leases In February 2019, the Company entered into a lease agreement for new office and laboratory space in South San Francisco, California. The term of the lease agreement commenced in May 2019. The lease has an initial term from occupancy of approximately ten years ending on December 31, 2029 with an option to extend the term for an additional eight years at then-market rental rates. The total base rent payment escalates annually based on a fixed percentage beginning from the 13 th In May 2016, the Company executed a non-cancellable lease agreement for office and laboratory space in Brisbane, California which commenced in May 2016 and continues through October 2022. The lease agreement includes an escalation clause for increased rent and a renewal provision allowing the Company to extend this lease for an additional four years by giving the landlord written notice of the election to exercise the option at least fifteen months prior to the original expiration of the lease term. The lease provides for monthly base rent amounts escalating over the term of the lease and the lessor provided the Company a $3.9 million tenant improvement allowance to complete the laboratory and office renovation which was recorded as deferred rent liability and leasehold improvements within property and equipment, net. In May 2017, the Company entered into an amendment to expand the leased space and received a three-month rent holiday for the expanded space. The Company’s operating leases include various covenants, indemnities, defaults, termination rights, security deposits and other provisions customary for lease transactions of this nature. The following table summarizes the components of lease expense, which are included in operating expenses in the Company’s condensed statements of operations and comprehensive loss (in thousands): Three Months Ended March 31, 2022 2021 Operating lease cost $ 1,078 $ 1,096 Variable lease cost 296 466 Sublease income (1,048 ) (145 ) Total lease cost $ 326 $ 1,417 Variable lease payments include amounts relating to common area maintenance, real estate taxes and insurance and are recognized in the condensed statements of operations and comprehensive loss as incurred. The following table summarizes supplemental information related to leases (in thousands): Three Months Ended March 31, 2022 2021 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,704 $ 1,652 Weighted-average remaining lease term (years) Operating leases 7.8 8.3 Weighted-average discount rate (percentage) Operating leases 6.0 % 5.9 % The following table summarizes the maturities of lease liabilities as of March 31, 2022 Amount 2022 (remaining 9 months) $ 4,579 2023 4,810 2024 4,964 2025 5,123 2026 5,287 Thereafter 16,893 Total future minimum lease payments 41,656 Less: Amount representing interest (8,391 ) Present value of future minimum lease payments 33,265 Less: Current portion of operating lease liability (3,926 ) Noncurrent portion of operating lease liability $ 29,339 In February 2020, the Company completed its move into the new office and laboratory space in South San Francisco, exited its previous offices and laboratory space in Brisbane, California, and began to actively market this space for sublease. Concurrent with this move and in consideration of real estate market conditions, in particular due to the COVID-19 pandemic in March 2020, the Company identified indicators of impairment in the related asset group, which included the leased ROU asset and related leasehold improvements associated with the lease. The Company subsequently evaluated and compared the net book value of the asset group to the estimated undiscounted future cash flows over the remaining term of the lease and concluded that an impairment had occurred. The discounted estimated future cash flows included estimates of sublease rentals through the end of the lease term, which ends on October 31, 2022, utilizing a discount rate of 3.5% based on the Company’s estimated incremental borrowing rate at that time. The estimated discounted cash flows were compared to the net book value of the ROU asset and leasehold improvements resulting in an impairment loss of $2.6 million during the year ended December 31, 2020, which was included in operating expense in the statements of operations and comprehensive loss. No impairment loss was recorded during the three months ended March 31, 2022. In February 2021, the Company entered into an agreement to sublease the first floor of the Brisbane, California facility, consisting of approximately 27,000 square feet, to Zymergen, Inc., through August 31, 2022. The base sublease rent rate is $3.53 per rental square foot per month and will increase by 3% on March 1, 2022 through expiration of the agreement. Additionally, the subtenant is required to pay approximately 41% of operating expenses and property management fees that the Company is required to pay under the lease for the Brisbane, California facility. In May 2021, the Company entered into an agreement to sublease the second floor of the Brisbane, California facility, consisting of approximately 11,500 square feet, to CareDx, Inc., through September 30, 2022. The base sublease rent rate is $1.00 per rental square foot per month through expiration of the agreement. Additionally, the subtenant is required to pay approximately 30% of operating expenses and property management fees that the Company is required to pay under the lease for the Brisbane, California facility. The Company incurred initial direct costs of $0.1 million in sublease commissions related to entering into the agreements to sublease the Brisbane, California facility. To account for the commissions, the Company capitalized the total commissions amount and will amortize the balance over the term of the sublease. Sublease income was $0.5 million and $0.1 million for the three months ended March 31, 2022 and 2021, respectively. In June 2021, the Company entered into an agreement to sublease a portion of the first floor of the South San Francisco, California facility, consisting of approximately 23,000 square feet, to Freenome Holdings, Inc., through August 31, 202 4 . The base sublease rent rate is $ 6.25 per rental square foot per month and will increase annually by 3.5 % through expiration of the agreement. Additionally, the subtenant is required to pay approximately 37 % of operating expenses and property management fees that the Company is required to pay under the lease for the South San Francisco, California facility. No impairment loss was recorded during the three months ended March 31, 2022 . Sublease income was $ million and zero for the three months ended March 31, 2022 and 2021 , respectively . Indemnifications The Company indemnifies each of its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with the Company’s amended and restated certificate of incorporation and bylaws. The term of the indemnification period lasts as long as an officer or director may be subject to any proceeding arising out of acts or omissions of such officer or director in such capacity. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director and officer liability insurance. This insurance allows the transfer of risk associated with the Company’s exposure and may enable the Company to recover a portion of any future amounts paid. The Company believes that the fair value of these potential indemnification obligations is minimal. Accordingly, the Company has not recognized any liabilities relating to these obligations for any period presented.

Term Loan Facility

Term Loan Facility	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Term Loan Facility	7. Term Loan Facility On August 3, 2020, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Hercules Capital, Inc. (“Hercules”). Under the Loan Agreement, Hercules provided the Company with access to a term loan with an aggregate principal amount of up to $80.0 million (the “Term Loan Facility”), available in four tranches, subject to certain terms and conditions. The first tranche of $25.0 million was advanced to the Company on the date the Loan Agreement was executed. The milestones for the remaining tranches have not yet been reached and as of March 31, 2022 are not expected to be reached as they were dependent, in whole or in part, upon continued advancement in the clinical development of UBX0101 in patients with osteoarthritis of the knee. On December 15, 2021, the Company entered into an amendment to the Loan and Security Agreement (“the Loan Amendment”). The Loan Amendment includes a Lender Optional Conversion where after the effective date and until the six-month During the first quarter of 2022, Hercules Capital, Inc. gave notice to convert the remaining convertible debt option into equity of the Company’s common stock. This resulted in the conversion of $2.7 million of principal debt into common stock, and reducing the outstanding principal under the first tranche to $20.0 million. The Company expects to make interest only payments through September 1, 2022 and expects to then repay the principal balance and interest in equal monthly installments through August 1, 2024. Pursuant to the Loan Amendment, the interest only period may extend up to a maximum of 9 months to June 1, 2023 should the company meet specific milestones related to its clinical trials and raising additional capital. The Company may prepay advances under the Loan Agreement, in whole or in part, at any time subject to a prepayment charge of up to 1.50% of any amount prepaid, depending upon when the prepayment occurs. Upon prepayment or repayment of all or any of the term loans under the Term Loan Facility, the Company is required to pay an end of term fee (“End of Term Fee”) equal to 6.25% of the total aggregate amount of the term loans being prepaid or repaid, which has been recorded as a discount on the principal balance upon issuance. Interest on the term loan accrues at a per annum rate equal to the greater of (i) the Wall Street Journal prime rate plus 6.10% and (ii) 9.35%. On March 17, 2022, the prime rate was raised to 3.50%. On March 31, 2022, the interest rate on the term loan was 9.60%. Interest expense is calculated using the effective interest method and is inclusive of non-cash amortization of capitalized loan issuance costs. At March 31, 2022, the effective interest rate was 17.26%. Under the terms of the Loan Agreement, the Company granted first priority liens and security interests in substantially all of the Company’s assets, other than intellectual property, as collateral for the obligations thereunder. We have determined that the risk of subjective acceleration under the material adverse events clause included in the Loan Agreement is remote and, therefore, have classified the outstanding principal amount in current and long-term liabilities based on the timing of scheduled principal payments. As of March 31, 2022, and as of the date of the issuance of these financial statements, the Company was in compliance with all covenants and has not been notified of an event of default by the lender under the Loan Agreement. As of March 31, 2022, the carrying value of the term loan consists of $20.0 million principal outstanding less the debt discount and issuance costs of approximately $2.2 million. The End of Term Fee of $1.6 million is recognized over the life of the term loan as interest expense using the effective interest method. The debt issuance costs have been recorded as a debt discount which are being accreted to interest expense through the maturity date of the term loan. Interest expense relating to the term loan, which is included in interest expense in the condensed statements of operations and comprehensive loss, was $0.8 million and $0.8 million for the three months ended March 31, 2022 and 2021, respectively. Future principal payments for the long-term debt as of March 31, 2022 are as follows (in thousands): Amount 2022 (for the remaining 9 months) $ 3,063 2023 9,813 2024 7,124 Total principal payments 20,000 End of term fee due at maturity in 2024 1,563 Total principal and end of term fee payments 21,563 Unamortized discount and debt issuance costs (2,192 ) Present value of remaining debt payments 19,371 Current portion of long-term debt (4,837 ) Long-term debt, net $ 14,534

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Related-Party Transactions	8. Related Party Transactions Licensing Revenue – Related Party In December 2021, the Company entered into a license agreement with Jocasta Neuroscience, Inc. A member of the Board of Directors of the Company is also an affiliate of Jocasta Neuroscience, Inc. The agreement provides for an upfront fee of $5.0 million and the opportunity for future research and development services to be provided. The Company recognized $4.8 million of licensing revenue for the year ended December 31, 2021. No licensing revenue was recognized for the three months ended March 31, 2022 and 2021. Recourse Notes In January 2018, the Company issued full-recourse promissory notes to a non-executive officer employee of the Company for an aggregate principal amount of $0.2 million with an interest rate of 2.5% per annum. All of the principal was used to early exercise options for 59,322 shares of the Company’s common stock. In December 2019, the full recourse note was deemed satisfied and superseded by a new full recourse promissory note agreement with a principal amount of $0.2 million and an interest rate of 1.51% per annum. In January 2021, the non-executive officer employee terminated his employment with the Company. As at March 31, 2021 the Company reclassified the $0.2 million recorded on the balance sheet in stockholders’ equity as ‘Related party promissory note for purchase of common stock’ to ‘Promissory notes for purchase of common stock’. The balance was repaid in full during the three months ended June 30, 2021.

Equity Financing

Equity Financing	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Equity Financing	9. Equity Financing At-the-Market Offering I n June 2019, the Company filed a Registration Statement on Form S-3 (the “Shelf Registration Statement”), covering the offering of up to $250.0 million of common stock, preferred stock, debt securities, warrants, and units. The Shelf Registration Statement included a prospectus covering the offering, issuance and sale of up to $75.0 million of the Company’s common stock from time to time through an “at-the-market” offering under the Securities Act of 1933, as amended (the “Initial ATM Offering Program”). The SEC declared the Shelf Registration Statement effective on June 6, 2019. In June 2019, the Company also entered into a sales agreement (the “June 2019 Sales Agreement”) with Cowen and Company, LLC (“Cowen”) to sell shares of the Company’s common stock, from time to time, with aggregate gross sales proceeds of up to $75.0 million, through the ATM Offering Program under which Cowen acts as its sales agent. Cowen is entitled to compensation for its services equal to up to 3.0% of the gross proceeds of any shares of common stock sold through Cowen under the June 2019 Sales Agreement. During the year ended December 31, 2020, the Company issued and sold 5,002,257 shares of its common stock through its ATM Offering Program and received net proceeds of approximately $37.3 million, after deducting commissions and other offering expenses of $1.3 million. I n July 2020, the Company filed an additional prospectus supplement to the Shelf Registration Statement. This prospectus supplement covers the offering, issuance and sale of up to an additional $50.0 million of the Company’s common stock from time to time through an additional “at-the-market” offering under the Securities Act of 1933, as amended (the “Additional ATM Offering Program”). The Initial ATM Offering Program and Additional ATM Offering Program are collectively (the “ATM Offering Programs”). In July 2020, the Company entered into a second sales agreement (the “July 2020 Sales Agreement”) with Cowen to sell shares of the Company’s common stock, from time to time, with aggregate gross sales proceeds of up to $50.0 million, through the Additional ATM Offering Program under which Cowen will act as its sales agent. The issuance and sale of shares of common stock by the Company pursuant to the July 2020 Sales Agreement are also deemed an “at-the-market” offering under the Securities Act of 1933, as amended (the “Securities Act”). Cowen is entitled to compensation for its services equal to up to 3.0% of the gross proceeds of any shares of common stock sold through Cowen under the July 2020 Sales Agreement. During the three months ended March 31, 2022, there were 2,325,000 shares of the Company’s common stock sold through the Additional ATM Offering Program and received total net proceeds of approximately $3.4 million, after deducting commissions and other offering expenses of $0.1 million. In March 2022, the Company entered into a third sales agreement (the “March 2022 Sales Agreement”) with Cowen to sell shares of the Company’s common stock, from time to time, with aggregate gross sales proceeds of up to $50.0 million. Equity Purchase Agreement On September 29, 2021, the Company entered into an equity purchase agreement (the “Purchase Agreement” or “Equity Purchase Agreement”) and a registration rights agreement with Lincoln Park Capital Fund, LLC (“Lincoln Park” or “Investor”) which provides for the sale to Lincoln Park up to $30,000,000 of shares (the “Purchase Shares”) of its common stock over the thirty-six (36) month term of the Purchase Agreement. In connection with the Purchase Agreement, Lincoln Park purchased 1,020,408 Purchase Shares at a purchase price of $2.94 per share, for a total gross purchase price of $3.0 million (the “Initial Purchase”), and the Company issued 252,447 shares of common stock to Lincoln Park as a commitment fee in connection with entering into the Purchase Agreement. The Company recognized $0.8 million of other expense relating to the commitment fee share issuance. As of December 31, 2021, the Company had initiated the purchase of an additional 2.9 million shares of the Company’s common stock amounting to $5.3 million in gross proceeds. During the three months ended March 31, 2022, the Company initiated purchases of an additional 0.9 million shares of the Company’s common stock amounting to $0.9 million in gross proceeds. Under the Purchase Agreement, the Company has sole discretion, subject to certain conditions, on any business day selected by the Company to require Lincoln Park to purchase up to 100,000 shares of common stock (the “Regular Purchase Amount”) at the Purchase Price (as defined below) per purchase notice (each such purchase, a “Regular Purchase”). The Regular Purchase Amount may be increased as follows: to up to 150,000 shares if the closing price is not below $3.50, up to 200,000 shares if the closing price is not below $5.00, and up to 250,000 shares if the closing price is not below $7.00. Lincoln Park’s committed obligation under each Regular Purchase is capped at $2,000,000, unless the Parties agree otherwise. The purchase price for Regular Purchases (the “Purchase Price”) shall be equal to the lesser of: (i) the lowest sale price of the common shares during the Purchase Date, or (ii) the average of the three (3) lowest closing sale prices of the common shares during the ten (10) business days prior to the Purchase Date. In addition to Regular Purchases and subject to certain conditions and limitations, the Company in its sole discretion may require Lincoln Park on each Purchase Date to purchase on the following business day up to the lesser of (i) three (3) times the number of shares purchased pursuant to such Regular Purchase or (ii) 30% of the trading volume on the Accelerated Purchase Date (the “Accelerated Purchase”) (unless the Parties agree otherwise) at a purchase price equal to the lesser of 97% of (i) the closing sale price on the Accelerated Purchase Date, or (ii) the Accelerated Purchase Date’s volume weighted average price (the “Accelerated Purchase Price”). The Company has the sole right to set a minimum price threshold for each Accelerated Purchase in the notice provided with respect to such Accelerated Purchase and under certain circumstances and in accordance with the Purchase Agreement the Company may direct multiple Accelerated Purchases in a day . The aggregate number of shares that the Company can sell to Lincoln Park under the Purchase Agreement may not exceed 11,065,803 shares of the Common Shares (which is equal to approximately 19.99% of the shares of the Common Shares outstanding immediately prior to the execution of the Purchase Agreement) (the “Exchange Cap”), unless (i) shareholder approval is obtained to issue Purchase Shares above the Exchange Cap, in which the Exchange Cap will no longer apply, or (ii) the average price of all applicable sales of Common Shares to Lincoln Park under the Purchase Agreement equals or exceeds $2.94 per share; provided that at no time may Lincoln Park (together with its affiliates) beneficially own more than 9.99% of the Company’s issued and outstanding Common Shares. The Purchase Agreement contains customary representations, warranties, covenants, closing conditions, indemnification and termination provisions. The Purchase Agreement may be terminated by the Company at any time, at its sole discretion, without any cost or penalty, by giving one business day notice to Lincoln Park. Further, Lincoln Park has covenanted not to engage in any direct or indirect short selling or hedging of the Common Shares. There are no limitations on the use of proceeds, financial or business covenants, restrictions on future financings (other than restrictions on the Company’s ability to enter into a similar type of agreement or Equity Line of Credit during the Term, excluding an At-The-Market transaction with a registered broker-dealer), rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement.

Corporate Restructuring

Corporate Restructuring	3 Months Ended
	Mar. 31, 2022
Restructuring And Related Activities [Abstract]
Corporate Restructuring	10 . Corporate Restructuring In February 2022, the Company implemented a corporate restructuring to align its resources to focus on its UBX1325 program while further extending operating capital. The restructuring is expected to result in an elimination of approximately 32 positions, or approximately 50% of the Company’s workforce, by the first half of 2022. The Company will incur a one-time employee benefits and severance charge of approximately $2.0 million in operating expenses in the first half of 2022. The related accrual is recorded in accrued compensation on the condensed balance sheet at March 31, 2022. Restructuring charges incurred under this plan primarily consisted of employee termination benefits. Employee termination benefits include $1.7 million of severance costs, $0.2 million of employee-related benefits, $0.1 million of payroll taxes and supplemental one-time termination payments. Charges and other costs related to the workforce reduction and structure realignment, and non-cash share-based compensation credits related to the forfeiture of stock options for $0.3 million are included in operating expenses in the condensed statements of operations and comprehensive loss. Of the total charge, $1.2 million was recorded to research and development expenses and $0.4 million was recorded to general and administrative expenses during the quarter ended March 31, 2022. The Company may also incur additional costs not currently contemplated due to events that may occur as a result of, or that are associated with, the restructuring. The Company may also incur additional costs not currently contemplated due to events that may occur as a result of, or that are associated with, the restructuring.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	11 . Stock-Based Compensation Stock Options and Restricted Stock Units Activity A summary of the Company’s stock option activity under the 2013 Equity Incentive Plan, 2018 Incentive Award Plan, and 2020 Employment Inducement Incentive Plan for the three months ended March 31, 2022 is as follows: Number of Shares Weighted- Average Exercise Price Balances at December 31, 2021 8,666,955 $ 6.05 Granted 1,897,085 $ 1.06 Exercised — $ — Canceled (717,266 ) $ 6.15 Balances at March 31, 2022 9,846,774 $ 5.08 A summary of the Company’s restricted stock units (“RSUs”), performance stock units (“PSUs”), and restricted stock awards (“RSAs”) activity for the three months ended March 31, 2022 is as follows: Number of Shares Weighted- Average Grant Date Fair Value Unvested at December 31, 2021 1,990,937 $ 3.92 Granted 463,328 $ 1.06 Vested (303,588 ) $ 4.48 Canceled (152,319 ) $ 3.54 Unvested at March 31, 2022 1,998,358 $ 3.20 For stock options granted to employees with service-based vesting, the fair value of stock options granted to employees was estimated on the date of grant using the Black-Scholes option pricing model and utilizing assumptions that were determined as follows: Expected Term —The expected term represents the period that the options granted are expected to be outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term) as the Company has concluded that its stock option exercise history does not provide a reasonable basis upon which to estimate expected term. Expected Volatility —Due to limited historical data, the Company estimates stock price volatility based on a combined weighted - average of the Company’s historical average volatility and that of a selected peer group of comparable publicly traded companies within the biotechnology and pharmaceutical industry that were deemed to be representative of future stock price trends over the expected life of the award. Risk-Free Interest Rate —The Company based the risk-free interest rate over the expected term of the options based on the constant maturity rate of U.S. Treasury securities with similar maturities as of the date of the grant. Expected Dividends —The Company has never paid any dividends and does not plan to pay dividends in the foreseeable future. Therefore, the expected dividend yield is zero. In March 2020, the board of directors granted the Company’s newly hired Chief Executive Officer stock-based awards covering an aggregate of 1.1 million shares of common stock, including options to purchase an aggregate of 800,000 shares of common stock, 120,000 RSUs, 150,000 PSUs, and 30,000 shares of common stock. The stock-based awards were granted pursuant to the 2020 Employment Inducement Incentive Plan, which was approved by the board of directors in March 2020 to provide for grants to newly hired employees as a material inducement for them to commence employment with the Company. The 30,000 shares of common stock were fully vested on the date of grant and thus, the related compensation expense of $0.2 million was recognized on the grant date. The stock options and RSUs will vest subject to continued service through the applicable vesting date. The PSUs were originally scheduled to vest as to 50,000 PSUs upon the attainment of (a) a volume-weighted average per share closing trading price of the Company’s common stock of at least $36.875 over a trailing 30-day period or (b) a change in control transaction in which the price per share to the holders of the Company’s common stock is at least $36.875 and as to 100,000 PSUs (x) at such time as the Company’s market capitalization reaches at least $2.5 billion, as measured based on the volume weighted-average closing trading price over a trailing 30 day period or (y) a change in control transaction in which the consideration paid to the Company’s stockholders is equal to at least $2.5 billion, as determined by the Company’s board of directors. In January 2021, the board of directors modified the PSUs to vest as to 50,000 PSUs upon the attainment of (a) a volume-weighted average per share closing trading price of the Company’s common stock of at least $18 over a trailing 30-day period or (b) a change in control transaction in which the price per share to the holders of the Company’s common stock is at least $18.00 and as to 100,000 PSUs upon the attainment of (x) a volume-weighted average per share closing trading price of the Company’s common stock of at least $36.00 over a trailing 30-day period or (y) a change in control transaction in which the price per share to the holders of the Company’s common stock is at least $36.00 , as determined by the Company’s board of directors . For the PSU awards, the Company used the Monte-Carlo option pricing model to determine the fair value of awards at the date of grant. The Monte-Carlo option pricing model uses similar input assumptions as the Black-Scholes model; however, it further incorporates into the fair-value determination the possibility that the market condition may not be satisfied. Compensation costs related to awards with a market-based condition are recognized regardless of whether the market condition is ultimately satisfied. Compensation cost is not reversed if the achievement of the market condition does not occur. The total grant date fair value of the PSU awards was determined to be $0.7 million and will be recognized as compensation expense over the weighted-average derived service period of approximately 4.3 years. In February 2022, the Company’s board of directors approved the granting of retention awards to critical and important Company personnel. The awards consisted of 1,893,335 stock options and 463,328 restricted stock units with a grant date total fair value of $2.0 million and $0.5 million, respectively . Performance and Market Contingent Stock Options In January 2021, the board of directors modified 17,479 performance and market contingent stock options with vesting conditions that required the combination of a liquidity event, change of control or IPO with a market condition at prescribed levels. The modification removed the performance condition and lowered the market conditions to a volume-weighted average per share closing trading price of the Company’s common stock of at least $ 18.00 over a trailing 30-day period for one tranche and at least $ 36.00 over a trailing 30-day period for the second tranche. The fair value of the options on the modification date of $ 81,000 will be amortized to expense over the implied service periods of 1.46 years to 2.52 years . In June 2021, the board of directors modified 33,370 performance and market contingent stock options with vesting conditions that required the combination of a liquidity event, change of control or IPO with a market condition at prescribed levels. The modification removed the performance condition and adjusted the market conditions to a date on which the Company attains a valuation of at least one billion dollars measured by the volume-weighted average per share closing trading price of the Company’s common stock over a trailing 30-day period. The fair value of the options on the modification date of $102,000 will be amortized to expense over the implied service periods of 1.85 years. As of March 31, 2022, there were 50,849 market contingent stock option awards outstanding with a total fair value of $0.2 million. Stock Based Compensation Expense The following table sets forth the total stock-based compensation expense for all options granted to employees and nonemployees, including shares sold through the issuance of non-recourse promissory notes which are considered to be options for accounting purposes, and costs associated with the Company’s 2018 Employee Stock Purchase Plan (“2018 ESPP”) included in the Company’s condensed statements of operations and comprehensive loss (in thousands): Three months ended March 31, 2022 2021 Research and development $ 1,004 $ 1,081 General and administrative 1,656 1,663 Total $ 2,660 $ 2,744 There was no stock-based compensation expense related to awards accounted for as liability awards for the three months ended March 31, 2022 and 2021.

Net Loss per Common Share

Net Loss per Common Share	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Net Loss per Common Share	12 . Net Loss per Common Share Basic net loss per share is calculated by dividing net loss by the weighted-average number of shares outstanding for the period. Diluted net loss per share is calculated by dividing net loss by the weighted-average number of shares of common stock and potential dilutive common stock equivalents outstanding during the period if the effect is dilutive. The calculation of diluted earnings (loss) per share also requires that, to the extent contingencies are satisfied during the period and the presumed issuance of additional shares as contingent consideration is dilutive to earnings (loss) per share for the period, adjustments to net income or net loss used in the calculation are required to remove the change in fair value of the contingent consideration liability for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares. In all periods presented, the Company’s outstanding stock options, RSUs (including PSUs), early exercised common stock subject to future vesting, restricted stock accounted for as options, shares subject to the 2018 ESPP and presumed issuance of additional shares as contingent consideration were excluded from the calculation of diluted net loss per share because their effects were antidilutive. A reconciliation of the numerators and denominators used in computing net loss from continuing operations per share is as follows (in thousands, except share and per share amounts): Three months ended March 31, 2022 2021 Numerator: Net loss $ (18,915 ) $ (15,756 ) Denominator: Weighted-average number of shares outstanding—basic and diluted 67,528,552 54,169,349 Net loss per share—basic and diluted $ (0.28 ) $ (0.29 ) Since the Company was in a net loss position for all periods presented, basic net loss per common share is the same as diluted net loss per common share as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: March 31, 2022 2021 Options to purchase common stock 9,846,774 7,405,619 Early exercised common stock subject to future vesting 33,370 33,370 RSUs 1,998,358 2,830,632 Shares subject to 2018 ESPP 145,017 57,568 Total 12,023,519 10,327,189 Up to 55,900 shares may be contingently issued, if certain performance conditions are met under the Company’s in-licensing agreements. See Note 5, “License Revenue and Agreements,” to our condensed financial statements for additional information.

Defined Contribution Plan

Defined Contribution Plan	3 Months Ended
	Mar. 31, 2022
Compensation And Retirement Disclosure [Abstract]
Defined Contribution Plan	13. Defined Contribution Plan The Company sponsors a 401(k) Plan that stipulates that eligible employees can elect to contribute to the 401(k) Plan, subject to certain limitations, on a pretax basis. In January 2019, the Company began to match 4% of employees’ salary. During the three months ended March 31, 2022 and 2021, the Company recorded matching contributions of $0.2 million and $0.2 million, respectively.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for interim reporting. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted. Accordingly, the unaudited condensed financial statements should be read in conjunction with the audited financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 filed with the SEC.
Unaudited Condensed Financial Statements	Unaudited Condensed Financial Statements The accompanying financial information for the three months ended March 31, 2022 and 2021 are unaudited. The unaudited condensed financial statements have been prepared on the same basis as the annual audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position as of March 31, 2022 and its results of operations for the three months ended March 31, 2022 and 2021 and cash flows for the three months ended March 31, 2022 and 2021. The results for interim periods are not necessarily indicative of the results expected for the full fiscal year or any other periods.
Use of Estimates	Use of Estimates The condensed financial statements have been prepared in accordance with GAAP, which requires management to make estimates and assumptions that affect the amounts and disclosures reported in the condensed financial statements and accompanying notes. The Company bases its estimates on historical experience and market-specific or other relevant assumptions that it believes are reasonable under the circumstances. The amounts of assets and liabilities reported in the Company’s condensed balance sheets and the amount of expenses and income reported for each of the periods presented are affected by estimates and assumptions, which are used for, but are not limited to, determining the fair value of assets and liabilities, contingent consideration liability, the fair value of right-of-use assets and lease liabilities, derivative liabilities related to debt and stock-based compensation. Actual results could differ from such estimates or assumptions.
Segments	Segments The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purposes of allocating resources.
Restructurings	Restructuring The Company recognizes restructuring charges related to reorganization plans that have been committed to by management and when liabilities have been incurred. In connection with these activities, the Company records restructuring charges at fair value for a) contractual employee termination benefits when obligations are associated to services already rendered, rights to such benefits have vested, and payment of benefits is probable and can be reasonably estimated, and b) one-time employee termination benefits when management has committed to a plan of termination, the plan identifies the employees and their expected termination dates, the details of termination benefits are complete, it is unlikely changes to the plan will be made or the plan will be withdrawn and communication to such employees has occurred. One-time employee termination benefits are recognized in their entirety when communication has occurred, and future services are not required. Contract termination costs to be incurred over the remaining contract term without economic benefit are recorded in their entirety when the contract is canceled. The recognition of restructuring charges requires the Company to make certain judgments and estimates regarding the nature, timing and amount of costs associated with the planned reorganization plan. At the end of each reporting period, the Company evaluates the remaining accrued restructuring balances to ensure that no excess accruals are retained, and the utilization of the provisions are for their intended purpose in accordance with developed restructuring plans.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In October 2020, the FASB issued ASU 2020-10, Codification Improvements In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments
Fair Value Measurements	The Company determines the fair value of financial and non-financial assets and liabilities based on the assumptions that market participants would use in pricing the asset or liability in an orderly transaction between market participants at the measurement date. The identification of market participant assumptions provides a basis for determining what inputs are to be used for pricing each asset or liability. A fair value hierarchy has been established which gives precedence to fair value measurements calculated using observable inputs over those using unobservable inputs. This hierarchy prioritized the inputs into three broad levels as follows: • Level 1: Quoted prices in active markets for identical instruments • Level 2: Other significant observable inputs (including quoted prices in active markets for similar instruments) • Level 3: Significant unobservable inputs (including assumptions in determining the fair value of certain investments)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Subject to Fair Value Measurements on Recurring Basis and Level of Inputs Used in Measurements	The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements were as follows (in thousands): March 31, 2022 Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 9,766 $ 9,766 $ — $ — U.S. treasuries 2,000 — 2,000 — Total cash equivalents 11,766 9,766 2,000 — Short-term marketable securities: U.S. treasuries 59,709 — 59,709 — U.S. government debt securities 3,008 — 3,008 — Total short-term marketable securities 62,717 — 62,717 — Total assets subject to fair value measurements on a recurring basis $ 74,483 $ 9,766 $ 64,717 $ — December 31, 2021 Total Level 1 Level 2 Level 3 Assets: Cash equivalents: Money market funds $ 21,421 $ 21,421 $ — $ — Total cash equivalents 21,421 21,421 — — Short-term marketable securities: U.S. treasuries 52,146 — 52,146 — U.S. government debt securities 3,024 — 3,024 — Total short-term marketable securities 55,170 — 55,170 — Long-term marketable securities: U.S. treasuries 1,993 — 1,993 — Total long-term marketable securities 1,993 — 1,993 — Total assets subject to fair value measurements on a recurring basis $ 78,584 $ 21,421 $ 57,163 $ —
Summary of Reconciliation of Derivative Liability Related to Debt Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs	The following table provides a reconciliation of the derivative liability related to debt measured at fair value on a recurring basis using significant unobservable inputs (Level 3) (in thousands): Derivative Liability related to Debt Conversion Feature ( 1) Balance at December 31, 2021 $ 963 Additions — Conversion (963 ) Change in fair value — Balance at March 31, 2022 $ —

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2022
Investments Debt And Equity Securities [Abstract]
Summary of Marketable Securities Classified as Available-for-Sale	Marketable securities, which are classified as available-for-sale, consisted of the following as of March 31, 2022 (in thousands): Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds $ 9,766 $ — $ — $ 9,766 U.S. treasuries 2,000 — — 2,000 Total cash equivalents 11,766 — — 11,766 Short-term marketable securities: U.S. government debt securities 3,016 — (8 ) 3,008 U.S. treasuries 59,877 — (168 ) 59,709 Total short-term marketable securities 62,893 — (176 ) 62,717 Total $ 74,659 $ — $ (176 ) $ 74,483 Marketable securities, which are classified as available-for-sale, consisted of the following as of December 31, 2021 (in thousands): Amortized Cost Basis Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds $ 21,421 $ — $ — $ 21,421 Total cash equivalents 21,421 — — 21,421 Short-term marketable securities: U.S. government debt securities 3,026 — (2 ) 3,024 U.S. treasuries 52,186 — (40 ) 52,146 Total short-term marketable securities 55,212 — (42 ) 55,170 Long-term marketable securities U.S. treasuries 1,995 — (2 ) 1,993 Total long-term marketable securities 1,995 — (2 ) 1,993 Total $ 78,628 $ — $ (44 ) $ 78,584

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Summary of Components of Lease Expense	The following table summarizes the components of lease expense, which are included in operating expenses in the Company’s condensed statements of operations and comprehensive loss (in thousands): Three Months Ended March 31, 2022 2021 Operating lease cost $ 1,078 $ 1,096 Variable lease cost 296 466 Sublease income (1,048 ) (145 ) Total lease cost $ 326 $ 1,417
Summary of Supplemental Information Related to Leases	The following table summarizes supplemental information related to leases (in thousands): Three Months Ended March 31, 2022 2021 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 1,704 $ 1,652 Weighted-average remaining lease term (years) Operating leases 7.8 8.3 Weighted-average discount rate (percentage) Operating leases 6.0 % 5.9 %
Summary of Maturities of Lease Liabilities	The following table summarizes the maturities of lease liabilities as of March 31, 2022 Amount 2022 (remaining 9 months) $ 4,579 2023 4,810 2024 4,964 2025 5,123 2026 5,287 Thereafter 16,893 Total future minimum lease payments 41,656 Less: Amount representing interest (8,391 ) Present value of future minimum lease payments 33,265 Less: Current portion of operating lease liability (3,926 ) Noncurrent portion of operating lease liability $ 29,339

Term Loan Facility (Tables)

Term Loan Facility (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Schedule of Future Principal Payments for Long-Term Debt	Future principal payments for the long-term debt as of March 31, 2022 are as follows (in thousands): Amount 2022 (for the remaining 9 months) $ 3,063 2023 9,813 2024 7,124 Total principal payments 20,000 End of term fee due at maturity in 2024 1,563 Total principal and end of term fee payments 21,563 Unamortized discount and debt issuance costs (2,192 ) Present value of remaining debt payments 19,371 Current portion of long-term debt (4,837 ) Long-term debt, net $ 14,534

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity	A summary of the Company’s stock option activity under the 2013 Equity Incentive Plan, 2018 Incentive Award Plan, and 2020 Employment Inducement Incentive Plan for the three months ended March 31, 2022 is as follows: Number of Shares Weighted- Average Exercise Price Balances at December 31, 2021 8,666,955 $ 6.05 Granted 1,897,085 $ 1.06 Exercised — $ — Canceled (717,266 ) $ 6.15 Balances at March 31, 2022 9,846,774 $ 5.08
Summary of Restricted Stock Units, Performance Stock Units and Restricted Stock Awards Activity	A summary of the Company’s restricted stock units (“RSUs”), performance stock units (“PSUs”), and restricted stock awards (“RSAs”) activity for the three months ended March 31, 2022 is as follows: Number of Shares Weighted- Average Grant Date Fair Value Unvested at December 31, 2021 1,990,937 $ 3.92 Granted 463,328 $ 1.06 Vested (303,588 ) $ 4.48 Canceled (152,319 ) $ 3.54 Unvested at March 31, 2022 1,998,358 $ 3.20
Summary of Stock-based Compensation Expense	The following table sets forth the total stock-based compensation expense for all options granted to employees and nonemployees, including shares sold through the issuance of non-recourse promissory notes which are considered to be options for accounting purposes, and costs associated with the Company’s 2018 Employee Stock Purchase Plan (“2018 ESPP”) included in the Company’s condensed statements of operations and comprehensive loss (in thousands): Three months ended March 31, 2022 2021 Research and development $ 1,004 $ 1,081 General and administrative 1,656 1,663 Total $ 2,660 $ 2,744

Net Loss per Common Share (Tabl

Net Loss per Common Share (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Schedule of Reconciliation of Numerators and Denominators Used In Computing Net Loss From Continuing Operations Per Share	A reconciliation of the numerators and denominators used in computing net loss from continuing operations per share is as follows (in thousands, except share and per share amounts): Three months ended March 31, 2022 2021 Numerator: Net loss $ (18,915 ) $ (15,756 ) Denominator: Weighted-average number of shares outstanding—basic and diluted 67,528,552 54,169,349 Net loss per share—basic and diluted $ (0.28 ) $ (0.29 )
Summary of Potentially Dilutive Securities Excluded from Computation of Diluted Per Share	Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows: March 31, 2022 2021 Options to purchase common stock 9,846,774 7,405,619 Early exercised common stock subject to future vesting 33,370 33,370 RSUs 1,998,358 2,830,632 Shares subject to 2018 ESPP 145,017 57,568 Total 12,023,519 10,327,189

Organization - Additional Infor

Organization - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	[1]
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit	$ (418,939)		$ (400,024)
Net loss	(18,915)	$ (15,756)
Cash used in operations	(14,972)	(15,091)
Product revenue	0	$ 0
Cash, cash equivalents and marketable securities	$ 79,200
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022Segment
Accounting Policies [Abstract]
Number of operating segment	1

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Subject to Fair Value Measurements on Recurring Basis and Level of Inputs Used in Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets:
Short-term marketable securities	$ 62,717	$ 55,170	[1]
Long-term marketable securities	0	1,993	[1]
Fair Value, Recurring
Assets:
Cash equivalents	11,766	21,421
Short-term marketable securities	62,717	55,170
Long-term marketable securities		1,993
Total assets subject to fair value measurements on a recurring basis	74,483	78,584
Fair Value, Recurring | Level 1
Assets:
Cash equivalents	9,766	21,421
Total assets subject to fair value measurements on a recurring basis	9,766	21,421
Fair Value, Recurring | Level 2
Assets:
Cash equivalents	2,000
Short-term marketable securities	62,717	55,170
Long-term marketable securities		1,993
Total assets subject to fair value measurements on a recurring basis	64,717	57,163
Money market funds | Fair Value, Recurring
Assets:
Cash equivalents	9,766	21,421
Money market funds | Fair Value, Recurring | Level 1
Assets:
Cash equivalents	9,766	21,421
U.S. Treasuries | Fair Value, Recurring
Assets:
Cash equivalents	2,000
Short-term marketable securities	59,709	52,146
Long-term marketable securities		1,993
U.S. Treasuries | Fair Value, Recurring | Level 2
Assets:
Cash equivalents	2,000
Short-term marketable securities	59,709	52,146
Long-term marketable securities		1,993
U.S. government debt securities | Fair Value, Recurring
Assets:
Short-term marketable securities	3,008	3,024
U.S. government debt securities | Fair Value, Recurring | Level 2
Assets:
Short-term marketable securities	$ 3,008	$ 3,024
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Reconciliation of Derivative Liability Related to Debt Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) - Fair Value, Recurring - Level 3 - Derivative Liability Related To Debt Conversion Feature $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)	[1]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance at December 31, 2021	$ 963
Conversion	(963)
Balance at March 31, 2022	$ 0
[1]	Transfers into Level 3 during the year ended December 31, 2021 relate to the call option with Hercules Capital, Inc, where the lender can convert principal debt into common stock. Transfers out of Level 3 during the year relate to the conversions calls of this option made by Hercules Capital, Inc.

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities Classified as Available-for-Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	$ 74,659	$ 78,628
Unrealized Gains	0	0
Unrealized Losses	(176)	(44)
Fair Value	74,483	78,584
Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	11,766	21,421
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	11,766	21,421
Cash Equivalents | Money market funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	9,766	21,421
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	9,766	21,421
Cash Equivalents | U S Treasuries
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	2,000
Unrealized Gains	0
Unrealized Losses	0
Fair Value	2,000
Short Term Marketable Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	62,893	55,212
Unrealized Gains	0	0
Unrealized Losses	(176)	(42)
Fair Value	62,717	55,170
Short Term Marketable Securities | U.S. government debt securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	3,016	3,026
Unrealized Gains	0	0
Unrealized Losses	(8)	(2)
Fair Value	3,008	3,024
Short Term Marketable Securities | U S Treasuries
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	59,877	52,186
Unrealized Gains	0	0
Unrealized Losses	(168)	(40)
Fair Value	$ 59,709	52,146
Long Term Marketable Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis		1,995
Unrealized Gains		0
Unrealized Losses		(2)
Fair Value		1,993
Long Term Marketable Securities | U S Treasuries
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis		1,995
Unrealized Gains		0
Unrealized Losses		(2)
Fair Value		$ 1,993

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Realized gains or losses on available-for-sale debt securities	$ 0	$ 0
Maximum
Marketable Securities [Line Items]
Available-for sale securities, remaining contractual maturity	1 year

License Revenue and Agreements

License Revenue and Agreements - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2019	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021		Aug. 31, 2021	Dec. 31, 2020
Research And Development Arrangement Contract To Perform For Others [Line Items]
Compound library and option agreement execution month and year			2016-02
Common stock, shares issued			69,148,106		62,991,906
Common stock, value			$ 7,000		$ 6,000	[1]
Licensed Products
Research And Development Arrangement Contract To Perform For Others [Line Items]
Royalties due from sales			0
License Agreement | Jocasta Neuroscience Inc
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront cash payments received					5,000,000
Revenue recognized			0	$ 0
Deferred revenue recognized			0	$ 0
Deferred revenue			200,000		200,000
Other Licensing Agreements with Research Institutions
Research And Development Arrangement Contract To Perform For Others [Line Items]
Contingent consideration, milestone or royalty payments			0		$ 0
Other Licensing Agreements with Research Institutions | UCSF
Research And Development Arrangement Contract To Perform For Others [Line Items]
Common shares expected to be issued		34,000
Contingent consideration, milestone or royalty payments			$ 0
Maximum milestone payments for each product licensed under agreement		$ 13,600,000
Other Licensing Agreements with Research Institutions | UCSF | Common Stock
Research And Development Arrangement Contract To Perform For Others [Line Items]
Issuance of common stock (in shares)		120,000
Other Licensing Agreements with Research Institutions | UCSF | Additional Paid-In Capital
Research And Development Arrangement Contract To Perform For Others [Line Items]
Issuance of common stock, net of issuance costs		$ 1,000,000
Commercial Agreements | Ascentage Pharma
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payments	$ 2,000,000
Equity payments percentage			80.00%
Common stock, shares issued			1,269,755				294,775	361,664
Common stock fair market value, net of withholding taxes							$ 1,100,000
Common stock, value								$ 2,300,000
Contingent consideration liability			$ 0
Commercial Agreements | Ascentage Pharma | Maximum
Research And Development Arrangement Contract To Perform For Others [Line Items]
Contingent consideration additional common stock issued for one licensed product			933,337
Contingent consideration additional common stock issued for two or more licensed product			1,333,338
Milestone payments			$ 70,300,000
Commercial Agreements | Ascentage Pharma | Initial License Agreement
Research And Development Arrangement Contract To Perform For Others [Line Items]
License agreement execution month and year			2016-02
Commercial Agreements | Ascentage Pharma | Second License Agreement
Research And Development Arrangement Contract To Perform For Others [Line Items]
License agreement execution month and year			2019-01
Commercial Agreements | Affiliate of Clinical-Stage Biopharmaceutical Company
Research And Development Arrangement Contract To Perform For Others [Line Items]
Equity payments percentage			20.00%
Common stock, shares issued			291,944				105,277
Common stock fair market value							$ 400,000
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	1 Months Ended			3 Months Ended		12 Months Ended
	Jun. 30, 2021ft²$ / ft²	May 31, 2021ft²$ / ft²	Feb. 28, 2021USD ($)ft²$ / ft²	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Commitments And Contingencies [Line Items]
Sublease income				$ 1,048,000	$ 145,000
South San Francisco, California
Commitments And Contingencies [Line Items]
Lessee, operating lease, description				In February 2019, the Company entered into a lease agreement for new office and laboratory space in South San Francisco, California. The term of the lease agreement commenced in May 2019. The lease has an initial term from occupancy of approximately ten years ending on December 31, 2029 with an option to extend the term for an additional eight years at then-market rental rates
Lease commencement date				2019-05
Lease expiration date				Dec. 31, 2029
Operating lease, initial lease term				10 years
Operating lease, option to extend description				option to extend the term for an additional eight years
Operating lease, existence of option to extend				true
Operating lease, renewal term				8 years
Tenant improvement allowance							$ 10,700,000
Letter of credit delivered in connection with lease agreement				$ 900,000
Estimated discount rate				3.50%
Impairment loss				$ 0		$ 2,600,000
Space subleased (in sqaure feet) | ft²	23,000
Sublease expiration date	Aug. 31, 2024
Sublease rent per square foot | $ / ft²	6.25
Annual percentage increase in sublease base rent	3.50%
Percentage of operating expenses and property management fees to be paid by subtenant	37.00%
Sublease income				$ 600,000	0
Brisbane, California
Commitments And Contingencies [Line Items]
Lease commencement date				2016-05
Operating lease, option to extend description				The lease agreement includes an escalation clause for increased rent and a renewal provision allowing the Company to extend this lease for an additional four years by giving the landlord written notice of the election to exercise the option at least fifteen months prior to the original expiration of the lease term.
Operating lease, renewal term				4 years
Tenant improvement allowance				$ 3,900,000
Lease expiration date				2022-10
Space subleased (in sqaure feet) | ft²		11,500	27,000
Sublease expiration date		Sep. 30, 2022	Aug. 31, 2022
Sublease rent per square foot | $ / ft²		1	3.53
Annual percentage increase in sublease base rent			3.00%
Percentage of operating expenses and property management fees to be paid by subtenant		30.00%	41.00%
Incurred initial direct costs of sublease			$ 100,000
Sublease income				$ 500,000	$ 100,000

Commitments and Contingencies_2

Commitments and Contingencies -Summary of Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Lease, Cost [Abstract]
Operating lease cost	$ 1,078	$ 1,096
Variable lease cost	296	466
Sublease income	(1,048)	(145)
Total lease cost	$ 326	$ 1,417

Commitments and Contingencies_3

Commitments and Contingencies - Summary of Supplemental Information Related to Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Operating cash flows from operating leases	$ 1,704	$ 1,652
Operating leases, Weighted-average remaining lease term (years)	7 years 9 months 18 days	8 years 3 months 18 days
Operating leases, Weighted-average discount rate (percentage)	6.00%	5.90%

Commitments and Contingencies_4

Commitments and Contingencies - Summary of Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	[1]
Commitments And Contingencies Disclosure [Abstract]
2022 (remaining 9 months)	$ 4,579
2023	4,810
2024	4,964
2025	5,123
2026	5,287
Thereafter	16,893
Total future minimum lease payments	41,656
Less: Amount representing interest	(8,391)
Present value of future minimum lease payments	33,265
Less: Current portion of operating lease liability	(3,926)
Noncurrent portion of operating lease liability	$ 29,339	$ 30,094
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Term Loan Facility - Additional

Term Loan Facility - Additional Information (Details) $ in Thousands	Mar. 17, 2022	Dec. 15, 2021USD ($)	Aug. 03, 2020USD ($)Tranche	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2021USD ($)	Jul. 01, 2021USD ($)
Debt Instrument [Line Items]
Debt instrument aggregate principal amount				$ 20,000
Unamortized discount and debt issuance costs				2,192
End of term fee due at maturity				1,563
Interest expense				808	$ 775
Term Loan | Loan Agreement
Debt Instrument [Line Items]
Debt conversion, original debt amount						$ 2,300
Loan issuance cost						$ 100
Term Loan | Loan Agreement | Maximum
Debt Instrument [Line Items]
Loan amendment conversion effective month of anniversary		6 months
Debt conversion percentage of principal amount		20.00%
Debt conversion, original debt amount		$ 5,000
Term Loan | Loan Agreement | Hercules Capital
Debt Instrument [Line Items]
Debt instrument aggregate principal amount				20,000
Number of tranches | Tranche			4
Principal amount of first tranche			$ 25,000	20,000
Debt conversion, original debt amount				$ 2,700
Long-term debt, maturity date				Aug. 1, 2024
Final payment fee of the total term loan advanced				6.25%
Debt instrument, interest rate terms				Interest on the term loan accrues at a per annum rate equal to the greater of (i) the Wall Street Journal prime rate plus 6.10% and (ii) 9.35%. On March 17, 2022, the prime rate was raised to 3.50%. On March 31, 2022, the interest rate on the term loan was 9.60%. Interest expense is calculated using the effective interest method and is inclusive of non-cash amortization of capitalized loan issuance costs. At March 31, 2022, the effective interest rate was 17.26%.
Debt instrument, interest rate, stated percentage				9.60%
Debt instrument, interest rate, effective percentage				17.26%
Maximum amount of debt that can be purchased by lender.				$ 2,000
Debt instrument, minimum unrestricted cash							$ 15,000
Unamortized discount and debt issuance costs				2,200
End of term fee due at maturity				1,600
Term Loan | Loan Agreement | Hercules Capital | Interest And Other Expense
Debt Instrument [Line Items]
Interest expense				$ 800	$ 800
Term Loan | Loan Agreement | Hercules Capital | Wall Street Journal Prime Rate
Debt Instrument [Line Items]
Debt instrument, interest rate, basis spread on variable rate				6.10%
Debt instrument, interest rate during period	3.50%
Term Loan | Loan Agreement | Hercules Capital | Maximum
Debt Instrument [Line Items]
Debt instrument aggregate principal amount			$ 80,000
Prepayment fee				1.50%
Term Loan | Loan Agreement | Hercules Capital | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				9.35%

Term Loan Facility - Schedule o

Term Loan Facility - Schedule of Future Principal Payments for Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	[1]
Debt Disclosure [Abstract]
2022 (for the remaining 9 months)	$ 3,063
2023	9,813
2024	7,124
Total principal payments	20,000
End of term fee due at maturity in 2024	1,563
Total principal and end of term fee payments	21,563
Unamortized discount and debt issuance costs	(2,192)
Present value of remaining debt payments	19,371
Current portion of long-term debt	(4,837)	$ (3,055)
Long-term debt, net	$ 14,534	$ 18,409
[1]	The balance sheet as of December 31, 2021 is derived from the audited financial statements as of that date.

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Dec. 31, 2019	Jan. 31, 2018	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Non-executive Officer | Promissory Note
Related Party Transaction [Line Items]
Due from related parties	$ 200,000	$ 200,000
Promissory notes for purchase of common stock				$ 200,000
Interest rate	1.51%	2.50%
Non-executive Officer | Promissory Note | Common Stock
Related Party Transaction [Line Items]
Early exercise options in aggregate		59,322
License Agreement | Jocasta Neuroscience Inc
Related Party Transaction [Line Items]
Upfront cash payments received					$ 5,000,000
Deferred revenue recognized			$ 0	$ 0	$ 4,800,000

Equity Financing - Additional I

Equity Financing - Additional Information (Details) - USD ($)	Sep. 29, 2021	Mar. 31, 2022	Dec. 31, 2021	Jul. 31, 2020	Jun. 30, 2019	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Subsidiary Sale Of Stock [Line Items]
Equity financing, authorized amount					$ 250,000,000
At The Market Equity Offering Program
Subsidiary Sale Of Stock [Line Items]
Proceeds from sale of common stock						$ 3,420,000	$ 8,892,000
Issuance of common stock, value						$ 3,420,000	$ 8,892,000
At The Market Equity Offering Program | Cowen | June 2019 Sales Agreement
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock (in shares)									5,002,257
Proceeds from sale of common stock									$ 37,300,000
Payments for other offering expenses									$ 1,300,000
At The Market Equity Offering Program | Cowen | June 2019 Sales Agreement | Maximum
Subsidiary Sale Of Stock [Line Items]
Equity financing, authorized amount					$ 75,000,000
Percentage of gross sales proceeds of common stock payable as compensation					3.00%
At The Market Equity Offering Program | Cowen | July 2020 Sales Agreement
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock (in shares)						2,325,000
Proceeds from sale of common stock						$ 3,400,000
Payments for other offering expenses						$ 100,000
At The Market Equity Offering Program | Cowen | July 2020 Sales Agreement | Maximum
Subsidiary Sale Of Stock [Line Items]
Equity financing, authorized amount				$ 50,000,000
Percentage of gross sales proceeds of common stock payable as compensation				3.00%
At The Market Equity Offering Program | Cowen | March 2022 Sales Agreement | Maximum
Subsidiary Sale Of Stock [Line Items]
Equity financing, authorized amount		$ 50,000,000
At The Market Equity Offering Program | Common Stock
Subsidiary Sale Of Stock [Line Items]
Equity financing, authorized amount					$ 75,000,000
Issuance of common stock (in shares)						2,325,000	1,220,629
At The Market Equity Offering Program | Common Stock | March 2022 Sales Agreement
Subsidiary Sale Of Stock [Line Items]
Equity financing, authorized amount		$ 50,000,000
Equity Purchase Agreement | Lincoln Park Capital Fund LLC
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock (in shares)	1,020,408		2,900,000			900,000
Issuance of common stock, value						$ 910,000
Purchase agreement term	36 months
Share purchase price	$ 2.94
Total gross purchase price of share	$ 3,000,000
Regular purchase capped amount	$ 2,000,000
Percentage of trading volume	30.00%
Percentage of purchase price	97.00%
Percentage of shares issued to common shares outstanding immediately prior to the execution of the purchase agreement.	19.99%
Purchase agreement price per share	$ 2.94
Maximum percentage ownership of issued and outstanding shares	9.99%
Equity Purchase Agreement | Lincoln Park Capital Fund LLC | Purchase Agreement 3.50 Closing Price
Subsidiary Sale Of Stock [Line Items]
Regular purchase amount closing price per share	$ 3.50
Equity Purchase Agreement | Lincoln Park Capital Fund LLC | Purchase Agreement 5.00 Closing Price
Subsidiary Sale Of Stock [Line Items]
Regular purchase amount closing price per share	5
Equity Purchase Agreement | Lincoln Park Capital Fund LLC | Purchase Agreement 7.00 Closing Price
Subsidiary Sale Of Stock [Line Items]
Regular purchase amount closing price per share	$ 7
Equity Purchase Agreement | Lincoln Park Capital Fund LLC | Maximum
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock (in shares)	11,065,803
Issuance of common stock, value	$ 30,000,000
Equity Purchase Agreement | Lincoln Park Capital Fund LLC | Maximum | Purchase Agreement 3.50 Closing Price
Subsidiary Sale Of Stock [Line Items]
Regular purchase amount shares	150,000
Equity Purchase Agreement | Lincoln Park Capital Fund LLC | Maximum | Purchase Agreement 5.00 Closing Price
Subsidiary Sale Of Stock [Line Items]
Regular purchase amount shares	200,000
Equity Purchase Agreement | Lincoln Park Capital Fund LLC | Maximum | Purchase Agreement 7.00 Closing Price
Subsidiary Sale Of Stock [Line Items]
Regular purchase amount shares	250,000
Equity Purchase Agreement | Common Stock | Lincoln Park Capital Fund LLC
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock (in shares)	252,447					900,000
Proceeds from sale of common stock						$ 900,000		$ 5,300,000
Other expense related to the commitment shares issued to Lincoln Park Capital Fund	$ 800,000
Equity Purchase Agreement | Common Stock | Lincoln Park Capital Fund LLC | Regular Purchase Amount per Business Day | Maximum
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock (in shares)	100,000

Corporate Restructuring - Addit

Corporate Restructuring - Additional Information (Details) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	Feb. 28, 2022Position	Mar. 31, 2022USD ($)	Jun. 30, 2022USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring implementation date	2022-02
Number of positions eliminated | Position	32
Percentage of positions eliminated	50.00%
Non-cash share-based payment compensation credits to forfeiture of stock options		$ 0.3
Research And Development Expense
Restructuring Cost And Reserve [Line Items]
Severance charge in operating expenses		1.2
General And Administrative Expense
Restructuring Cost And Reserve [Line Items]
Severance charge in operating expenses		0.4
Employee Termination Benefits
Restructuring Cost And Reserve [Line Items]
Severance charge in operating expenses		1.7
Employee Termination Benefits | Employee-Related Benefits
Restructuring Cost And Reserve [Line Items]
Severance charge in operating expenses		0.2
Employee Termination Benefits | Payroll Taxes
Restructuring Cost And Reserve [Line Items]
Severance charge in operating expenses		$ 0.1
Scenario Forecast
Restructuring Cost And Reserve [Line Items]
Severance charge in operating expenses			$ 2

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details)	3 Months Ended
	Mar. 31, 2022$ / sharesshares
Number of Shares
Balances at December 31, 2021 | shares	8,666,955
Granted | shares	1,897,085
Canceled | shares	(717,266)
Balances at March 31, 2022 | shares	9,846,774
Weighted-Average Exercise Price
Balances at December 31, 2021 | $ / shares	$ 6.05
Granted | $ / shares	1.06
Canceled | $ / shares	6.15
Balances at March 31, 2022 | $ / shares	$ 5.08

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Restricted Stock Units, Performance Stock Units and Restricted Stock Awards Activity (Details) - RSU, RSA and PSU	3 Months Ended
	Mar. 31, 2022$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Unvested at December 31, 2021 | shares	1,990,937
Shares, Granted | shares	463,328
Shares, Vested | shares	(303,588)
Shares, Canceled | shares	(152,319)
Shares, Unvested at March 31, 2022 | shares	1,998,358
Weighted-Average Grant Date Fair Value, Unvested at December 31, 2021 | $ / shares	$ 3.92
Weighted-Average Grant Date Fair Value, Granted | $ / shares	1.06
Weighted-Average Grant Date Fair Value, Vested | $ / shares	4.48
Weighted-Average Grant Date Fair Value, Canceled | $ / shares	3.54
Weighted-Average Grant Date Fair Value, Unvested at March 31, 2022 | $ / shares	$ 3.20

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended				3 Months Ended
	Feb. 28, 2022	Jun. 30, 2021	Jan. 31, 2021	Mar. 31, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares options granted to purchase an aggregate of common stock					1,897,085
Compensation cost recognized				$ 200,000
Stock option awards outstanding					9,846,774		8,666,955
Stock based compensation expense for liability awards					$ 0	$ 0
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of retention awards granted	1,893,335
Retention award grant date total fair value	$ 2,000,000
RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of retention awards granted	463,328
Retention award grant date total fair value	$ 500,000
Performance and Market Contingent Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Trailing period		30 days
Modification date fair value		$ 102,000	$ 81,000
Implied service period for recognition		1 year 10 months 6 days
Stock option awards outstanding					50,849
Performance and Market Contingent Stock Options | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Implied service period for recognition			1 year 5 months 15 days
Attaining valuation of certain amount		$ 1,000,000,000
Performance and Market Contingent Stock Options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Implied service period for recognition			2 years 6 months 7 days
Performance and Market Contingent Stock Options | Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volume-weighted average per Share closing trading price			$ 18
Trailing period			30 days
Performance and Market Contingent Stock Options | Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volume-weighted average per Share closing trading price			$ 36
Trailing period			30 days
Performance and Market Contingent Stock Options | Executive Team
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option awards exercisable upon the achievement of performance goals		33,370	17,479
2020 Employment Inducement Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental fair value on modification date			$ 31,000
Unamortized value of original grant			$ 569,000
2020 Employment Inducement Incentive Plan | New Chief Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares granted				1,100,000
2020 Employment Inducement Incentive Plan | Stock Options | New Chief Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares options granted to purchase an aggregate of common stock				800,000
2020 Employment Inducement Incentive Plan | PSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value				$ 700,000
Weighted-average derived service period for recognition				4 years 3 months 18 days
2020 Employment Inducement Incentive Plan | PSUs | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
New implied service period for recognition				1 year 7 months 17 days
2020 Employment Inducement Incentive Plan | PSUs | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
New implied service period for recognition				2 years 9 months 14 days
2020 Employment Inducement Incentive Plan | PSUs | Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares to vest upon attainment of certain conditions			50,000	50,000
Volume-weighted average per Share closing trading price			$ 18	$ 36.875
Trailing period			30 days	30 days
2020 Employment Inducement Incentive Plan | PSUs | Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares to vest upon attainment of certain conditions			100,000	100,000
Trailing period			30 days	30 days
Price per share to holders of company's common stock			$ 36	$ 36.875
Market capitalization trigger				$ 2,500,000,000
2020 Employment Inducement Incentive Plan | PSUs | New Chief Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares options granted to purchase an aggregate of common stock				150,000
2020 Employment Inducement Incentive Plan | RSUs and Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting rights				The stock options and RSUs will vest subject to continued service through the applicable vesting date.
2020 Employment Inducement Incentive Plan | RSUs | New Chief Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares granted				120,000
2020 Employment Inducement Incentive Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares vested				30,000
2020 Employment Inducement Incentive Plan | Common Stock | New Chief Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares granted				30,000

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,660	$ 2,744
Research And Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,004	1,081
General And Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,656	$ 1,663

Net Loss per Common Share - Sch

Net Loss per Common Share - Schedule of Reconciliation of Numerators and Denominators Used In Computing Net Loss From Continuing Operations Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net loss	$ (18,915)	$ (15,756)
Denominator:
Weighted-average number of shares outstanding—basic and diluted	67,528,552	54,169,349
Net loss per share, basic and diluted	$ (0.28)	$ (0.29)

Net Loss per Common Share - Sum

Net Loss per Common Share - Summary of Potentially Dilutive Securities Excluded from Computation of Diluted Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	12,023,519	10,327,189
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	9,846,774	7,405,619
Early Exercised Common Stock Subject to Future Vesting
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	33,370	33,370
RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	1,998,358	2,830,632
Shares Subject to 2018 ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	145,017	57,568

Net Loss per Common Share - Add

Net Loss per Common Share - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022shares
Maximum
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Shares contingently issued	55,900

Defined Contribution Plan - Add

Defined Contribution Plan - Additional Information (Details) - Defined Contribution Plan - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2019	Mar. 31, 2022	Mar. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
Percent of employer matching contribution of employees' salary	4.00%
Defined Contribution Plan, Sponsor Location [Extensible Enumeration]	us-gaap:DomesticPlanMember
Matching contributions		$ 0.2	$ 0.2