Sierra Oncology (SRRA) 10-Q 6 May 22 2022 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2022	May 02, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Registrant Name	Sierra Oncology, Inc.
Entity Central Index Key	0001290149
Trading Symbol	SRRA
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding		24,419,349
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, $0.001 par value
Entity File Number	001-37490
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-0138994
Entity Address, Address Line One	1820 Gateway Drive, Suite 110
Entity Address, City or Town	San Mateo
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94404
City Area Code	650
Local Phone Number	376-8679
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
CURRENT ASSETS:
Cash and cash equivalents	$ 274,015	$ 104,749
Prepaid expenses and other current assets	4,182	2,644
Total current assets	278,197	107,393
Property and equipment, net	129	141
Operating lease right-of-use assets	708	788
Other assets	966	1,045
TOTAL ASSETS	280,000	109,367
CURRENT LIABILITIES:
Accrued and other liabilities	11,282	10,726
Accounts payable	1,798	2,158
Total current liabilities	13,080	12,884
Term loan	4,862
Operating lease liabilities	436	485
TOTAL LIABILITIES	18,378	13,369
Commitments and Contingencies (Note 8)
STOCKHOLDERS’ EQUITY:
Preferred stock, $0.001 par value; 10,000,000 shares authorized as of March 31, 2022 and December 31, 2021; nil shares issued and outstanding as of March 31, 2022 and December 31, 2021
Common stock, $0.001 par value; 500,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 23,800,409 and 15,571,656 shares issued and outstanding as of March 31, 2022 and December 31, 2021	24	16
Additional paid-in capital	1,230,774	1,037,230
Accumulated deficit	(969,176)	(941,248)
TOTAL STOCKHOLDERS’ EQUITY	261,622	95,998
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 280,000	$ 109,367

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	23,800,409	15,571,656
Common stock, shares outstanding	23,800,409	15,571,656

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses:
Research and development	$ 17,554	$ 13,953
General and administrative	10,329	5,865
Total operating expenses	27,883	19,818
Loss from operations	(27,883)	(19,818)
Other expense, net	59	29
Loss before provision for (benefit from) income taxes, net	(27,942)	(19,847)
Provision for (benefit from) income taxes, net	(14)	68
Net loss and comprehensive loss	$ (27,928)	$ (19,915)
Net loss per common share, basic and diluted	$ (1.33)	$ (1.71)
Weighted-average shares used in computing net loss per common share, basic and diluted	20,965,811	11,667,967

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Stockholders Equity, Beginning Balance at Dec. 31, 2020	$ 97,959	$ 11	$ 944,537	$ (846,589)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2020		11,128,484
Issuance of common stock	19,632	$ 1	19,631
Issuance of common stock, Shares		1,149,820
Issuance of common stock for exercise of common stock warrants	660		660
Issuance of common stock for exercise of common stock warrant, Shares		49,995
Issuance of common stock for exercise of common stock options	288		288
Issuance of common stock for exercise of common stock options, Shares		21,662
Stock-based compensation	2,931		2,931
Net loss	(19,915)			(19,915)
Stockholders Equity, Ending Balance at Mar. 31, 2021	101,555	$ 12	968,047	(866,504)
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2021		12,349,961
Stockholders Equity, Beginning Balance at Dec. 31, 2021	95,998	$ 16	1,037,230	(941,248)
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2021		15,571,656
Issuance of common stock	121,905	$ 5	121,900
Issuance of common stock, Shares		4,824,075
Issuance of pre-funded stock warrants	23,397		23,397
Issuance of common stock for exercise of common stock warrants	40,346	$ 3	40,343
Issuance of common stock for exercise of common stock warrant, Shares		3,056,477
Issuance of common stock for exercise of common stock options	4,572		4,572
Issuance of common stock for exercise of common stock options, Shares		348,201
Stock-based compensation	3,332		3,332
Net loss	(27,928)			(27,928)
Stockholders Equity, Ending Balance at Mar. 31, 2022	$ 261,622	$ 24	$ 1,230,774	$ (969,176)
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2022		23,800,409

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)
Net of offering costs	$ 8.3
Warrants [Member]
Net of offering costs	$ 1.6

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (27,928)	$ (19,915)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	3,332	2,931
Depreciation and amortization	92	47
Other	29	(11)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,459)	406
Accounts payable	(297)	317
Accrued, other and operating lease liabilities	494	(736)
Net cash used in operating activities	(25,737)	(16,961)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(62)
Net cash used in investing activities	(62)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of common stock warrants	40,346	660
Proceeds from issuance of pre-funded warrants in a public offering	23,397
Proceeds from issuance of term loan, net of issuance costs	4,845
Proceeds from exercise of common stock options	4,572	288
Net cash provided by financing activities	195,065	20,580
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash		(16)
NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	169,266	3,603
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period	105,049	104,355
CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period	274,315	107,958
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for income taxes, net	17	13
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION:
Unpaid deferred financing costs in accrued and other liabilities	63	110
Follow-on Offering [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock, net of offering costs	$ 121,905
At-The-Market Offering [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock, net of offering costs		$ 19,632

Organization

Organization	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	1. Description of Business Sierra Oncology, Inc. (together with its subsidiaries, collectively referred to as the “Company”), a Delaware corporation, is a late-stage biopharmaceutical company focused on the potential commercialization of momelotinib, an investigational agent for the treatment in myelofibrosis. Momelotinib is a selective and orally bioavailable JAK1 (Janus kinase 1), JAK2 (Janus kinase 2) and ACVR1 (Activin A receptor type 1) / activin receptor-like kinase-2 (ALK2) inhibitor with a differentiated mechanism of action. In January 2022, the Company announced positive topline results from its global Phase 3 clinical trial, called MOMENTUM, for patients with myelofibrosis who are symptomatic and anemic and previously treated with an approved JAK inhibitor. Momelotinib achieved a statistically significant benefit on symptoms, anemia and splenic size. The MOMENTUM data, combined with data from earlier clinical trials, will be the basis for a New Drug Application (NDA) that the Company plans to submit in the second quarter of 2022. Approximately 1,000 myelofibrosis patients have received momelotinib through clinical trials at different stages of clinical development, and several of these patients remain on treatment for more than 11 years. In August 2021, the Company acquired an exclusive global license from AstraZeneca AB (AstraZeneca) for SRA515 (formerly AZD5153), a potent and selective bromodomain-containing protein 4 ( The Company’s portfolio also includes SRA737, a selective, orally bioavailable small molecule inhibitor of Checkpoint kinase 1 (Chk1), an emerging target for the treatment of cancer which has a key role in the DNA Damage Response (DDR). The Company’s primary activities since inception have been conducting research and development activities, conducting preclinical and clinical testing, recruiting personnel, preparing for potential commercialization, performing business and financial planning, identifying and evaluating additional drug candidates for potential in-licensing or acquisition, and raising capital to support development activities. As of March 31, 2022, the Company had $274.0 million of cash and cash equivalents. The Company believes that its balance of cash and cash equivalents as of the date of the issuance of these consolidated financial statements is sufficient to fund its current operational plan for at least the next twelve months. Proposed Merger with GlaxoSmithKline On April 12, 2022, the Company entered into an Agreement and Plan of Merger (Merger Agreement) with GlaxoSmithKline plc, a public limited company organized under the laws of England and Wales (GSK) and Orikum Acquisition Inc., a Delaware corporation and wholly owned subsidiary of GSK (Acquisition Sub). The Merger Agreement provides that, subject to the terms and conditions set forth in the Merger Agreement, Acquisition Sub will merge with and into the Company (the Merger), with the Company surviving the Merger as an indirect wholly owned subsidiary of GSK. Treatment of Capital Stock - Treatment of Equity Awards - Treatment of Warrants - defined in the Series A Warrants) and (2) any of the Company’s outstanding pre-funded warrants will be deemed exercised in full as a “cashless exercise” (as described in the Pre-Funded Warrants), and the holder thereof will be entitled to receive an amount in cash, without interest, equal to the product obtained by multiplying (1) the amount of the Per Share Price by (2) the number of shares of the Company’s common stock deemed to be issuable upon exercise in full of the pre-funded warrant as a “cashless exercise.” Consummation of the Merger is subject to the satisfaction or waiver of customary closing conditions, including: (1) the approval of the Merger Agreement by holders of a majority of the outstanding shares of the Company’s common stock (Requisite Stockholder Approval); (2) the expiration or termination of the waiting period under the United States Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (HSR Act); and (3) the absence of any order, law or legal restraint preventing or materially impairing the consummation of the Merger. The Merger Agreement contains customary representations, warranties and covenants made by each of the Company, GSK and Acquisition Sub, including, among others, covenants by the Company regarding the conduct of its business prior to the closing of the Merger. Beginning on the date of the Merger Agreement, the Company is subject to customary “no-shop” restrictions pursuant to which the Company is required, among other things, (i) not to solicit, initiate, propose or induce the making or knowingly encourage any Acquisition Proposals (as defined in the Merger Agreement) and (ii) subject to certain exceptions, not to engage in discussions or negotiations regarding, or furnish to any third party any non-public information with respect to, any Acquisition Proposal. In addition, the Company has agreed that, subject to certain exceptions, the Company Board will not withdraw its recommendation that the Company’s stockholders vote to adopt and approve the Merger Agreement. The Company has also agreed that the Company will file with the SEC a proxy statement in preliminary form relating to the adoption of the Merger Agreement by the Company’s stockholders as promptly as reasonably practicable after the date of the Merger Agreement, and the Company will convene and hold a special meeting of the Company’s stockholders for the purpose of seeking the adoption of the Merger Agreement as promptly as reasonably practicable following the mailing of the definitive proxy statement to the Company’s stockholders. Either the Company or GSK may terminate the Merger Agreement if, among certain other circumstances, (i) the Merger has not been consummated on or before October 10, 2022 or (ii) the Company’s stockholders fail to adopt the Merger Agreement at the special meeting. The Company may terminate the Merger Agreement in certain additional limited circumstances, including to allow the Company to enter into a definitive agreement for an alternative acquisition proposal that constitutes a Superior Proposal (as defined in the Merger Agreement). GSK may terminate the Merger Agreement in certain additional limited circumstances, including if the Company Board withdraws its recommendation that the Company’s stockholders vote to adopt and approve the Merger Agreement, if the Company enters into an agreement relating to an Acquisition Proposal or if the “no shop” provisions of the Merger Agreement are willfully and materially breached. Upon termination of the Merger Agreement under specified circumstances, the Company will be required to pay GSK a termination fee of $70.0 million. Specifically, this termination fee is payable by the Company to GSK if the Merger Agreement is terminated by (1) GSK because (A) the Company Board withdraws its recommendation that the Company’s stockholders vote to adopt and approve the Merger Agreement, (B) the Company enters into an agreement relating to an Acquisition Proposal or (C) the “no shop” provisions of the Merger Agreement are willfully and materially breached; or (2) prior to receiving the Requisite Stockholder Approval, the Company in order to enter into a definitive agreement for an alternative acquisition proposal that constitutes a Superior Proposal. The termination fee will also be payable in certain circumstances if (1) the Merger Agreement is terminated under certain circumstances; (2) prior to such termination a proposal to acquire at least 50 percent of the Company’s stock or assets is made and not withdrawn; and (3) within one year of such termination, the Company subsequently enters into a definitive agreement providing for the acquisition of at least 50 percent of its stock or assets and such transaction is ultimately consummated. For additional information regarding the Merger, please refer to the Merger Agreement, which was filed with the SEC on April 13, 2022, as an exhibit to a Current Report on Form 8-K.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and applicable rules and regulations of the Securities and Exchange Commission (SEC) regarding interim financial reporting. Accordingly, they do not include all the information and notes required for complete financial statements and should be read in conjunction with the Company’s audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, filed with the SEC on March 10, 2022. There were no significant changes to the accounting policies during the three months ended March 31, 2022 from the significant accounting policies described in Note 2 to the consolidated financial statements in the 2021 Form 10-K. The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. These unaudited condensed consolidated financial statements and related disclosure have been prepared on the same basis as the annual consolidated financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s condensed consolidated financial statements included in this report. The condensed consolidated results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the year ending December 31, 2022 , or for any other future annual or interim period. The condensed consolidated balance sheet as of December 31, 2021 included herein was derived from the audited consolidated financial statements as of that date. Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of expense during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to the fair value of stock options issued, the probability of achieving performance-based milestones of stock options, accruals such as research and development costs, and recoverability of the Company’s net deferred tax assets and related valuation allowance. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	3. Basic net loss per share is calculated by dividing net loss by the weighted-average number of common stock outstanding during the period without consideration for common stock equivalents. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, stock options and warrants for common stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following shares of common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented because including them would have been antidilutive: March 31, 2022 March 31, 2021 Series A warrants for common stock 7,771,951 7,802,241 Series B warrants for common stock 212,477 2,524,732 Options to purchase common stock 5,466,822 4,667,173 Pre-funded warrants for common stock 925,925 — Warrants for common stock 1,839 727,122 Total potential dilutive shares 14,379,014 15,721,268

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. The Company measures and reports its cash equivalents at fair value. The following table sets forth the fair value of the Company’s financial assets measured on a recurring basis by level within the fair value hierarchy: March 31, 2022 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 271,564 $ — $ — $ 271,564 December 31, 2021 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 102,526 $ — $ — $ 102,526 Money market funds are measured at fair value on a recurring basis using quoted prices and are classified as a Level 1 input. The Company’s cash and cash equivalents, restricted cash, other current assets, accounts payable and accrued and other liabilities approximate their fair values due to their short duration. The term loan bears interest at prevailing market rates for instruments with similar characteristics, accordingly, the carrying value of this instrument approximates its fair value. There were no transfers between Levels 1, 2 or 3 during the three months ended March 31, 2022.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Components	5. Cash and Cash Equivalents Cash and cash equivalents consist of the following: March 31, 2022 December 31, 2021 (in thousands) Cash $ 2,451 $ 2,223 Cash equivalents: Money market accounts 271,564 102,526 Total cash and cash equivalents $ 274,015 $ 104,749 The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the condensed consolidated balance sheets to the amounts shown in the condensed consolidated statements of cash flows. March 31, 2022 March 31, 2021 (in thousands) Cash and cash equivalents $ 274,015 $ 107,658 Restricted cash included in other assets 300 300 Total cash, cash equivalents and restricted cash shown in the condensed consolidated statement of cash flows $ 274,315 $ 107,958 Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following: March 31, 2022 December 31, 2021 (in thousands) Prepaid research and development project costs $ 1,233 $ 290 Prepaid software and subscription fees 1,130 536 Prepaid insurance 556 1,029 Other receivables 270 147 Other 993 642 Total prepaid expenses and other current assets $ 4,182 $ 2,644 Property and Equipment, net Property and equipment, net consists of the following: March 31, 2022 December 31, 2021 (in thousands) Software $ 456 $ 456 Leasehold improvements 35 35 Computer equipment 5 5 Property and equipment, gross 496 496 Less: accumulated depreciation (367 ) (355 ) Total property and equipment, net $ 129 $ 141 Depreciation related to the Company’s property and equipment was $12,000 for the three months ended March 31, 2022 and $10,000 for the three months ended March 31, 2021. Accrued and Other Liabilities Accrued and other liabilities consist of the following: March 31, 2022 December 31, 2021 (in thousands) Accrued research and development costs $ 4,864 $ 2,727 Accrued employee related costs 3,383 6,725 Accrued professional fees 2,427 739 Operating lease liabilities 318 368 Other 290 167 Total accrued and other liabilities $ 11,282 $ 10,726

Leases

Leases	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Leases	6. In December 2020, the Company entered into a 48-month operating lease agreement to lease office space in San Mateo, California. The lease commenced on April 30, 2021 and expires on April 30, 2025. The Company also has an operating lease agreement to lease office space in Vancouver, Canada that expires on February 28, 2023. In December 2020, the Company entered into an agreement to sublet the entire office premises to a third party until February 27, 2023. Pursuant to the sublease agreement, the subtenant will pay base rent of $0.2 million per annum to the Company and all operating costs related to the office space. The components of lease expense and related cash flows for the three months ended March 31, 2022 and 2021 were as follows: Three Months Ended March 31, 2022 2021 (in thousands) Operating lease cost $ 89 $ 43 Short-term lease cost $ 7 7 96 50 Operating cash flows used for operating leases $ 110 $ 57 As of March 31, 2022, the weighted average remaining lease term and discount rate for the operating leases are 2.7 years and 4.6%, respectively. As of March 31, 2022, maturities of lease liability due under the lease agreements are as follows: Years Ending December 31: Operating Leases (in thousands) Remainder of 2022 289 2023 223 2024 230 2025 58 Total lease payments 800 Less imputed interest (46 ) Total 754 These amounts have not been reduced by future base rent due under the Vancouver sublease of $0.2 million. In addition to base rent, the Vancouver lease requires payment of operating costs. These costs are not included in the table above or the sublease amount.

Term Loan

Term Loan	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Term Loan	7. Term Loan On January 21, 2022 (Effective Date), the Company entered into a Loan and Security Agreement (Loan Agreement) with Oxford Finance, LLC (Oxford), pursuant to which the Company may obtain a loan of aggregate principal amount of up to $125.0 million (Term Loans) in four tranches. Contemporaneously with executing the Loan Agreement the achievement of certain pre-determined milestones. During the first quarter of 2022, the Company met the milestone required to borrow under Term Loan B but has elected to defer the draw and combine with Term Loan C for a total of a $ 70.0 million, per the terms of the Loan Agreement. Term Loan C must be drawn within 30 days after the completion of the related milestone but no later than December 31, 2023 . The $ 50.0 million under Term Loan D will only be available at the sole discretion of the lender. The Term Loans will bear interest at the floating per year rate equal to the prime rate, plus a margin of 5.25%, subject to a floor of 8.50% (for an interest rate of 8.50% at March 31, 2022). Interest is payable monthly in arrears on the first calendar day of each calendar month. Beginning (i) March 1, 2025, if either the Term B Loan or the Term C Loan is not made or (ii) September 1, 2025, if both the Term B Loan and the Term C Loan are made, the Company shall repay the Term Loans in consecutive equal monthly payments of principal, together with applicable interest, in arrears. All unpaid principal and accrued and unpaid interest with respect to each Term Loan is due and payable in full on January 1, 2027. The Company will be required to make a final payment of 6.0% of the original principal amount of the Term Loans, payable at maturity or upon any earlier acceleration or prepayment of the Term Loans. The Company may prepay all, but not less than all, of the Term Loans, subject to a prepayment fee equal to (i) 2.0% of the principal amount of the applicable Term Loan if prepaid on or before the first anniversary date of the Effective Date and (ii) 1.0% of the principal amount of the applicable Term Loan if prepaid after the first and on or before the third anniversary of the Effective Date. All Term Loans will be subject to a facility fee of 0.5% of the principal amount. The Company’s obligations under the Loan Agreement are secured by all its assets, other than its intellectual property, until the first date on which the aggregate outstanding principal amount of the Term Loans equals or exceeds $50.0 million, at which time the Company has agreed to grant a security interest in its intellectual property. The Loan Agreement contains customary affirmative and restrictive covenants, including, among others, covenants restricting the Company from incurring additional indebtedness, granting liens, making investments, consummating transactions with affiliates, disposing of assets, consummating mergers or acquisitions, having a change of control and paying dividends or distributions, subject in each case, to customary qualifications and exceptions. In addition, beginning with the fiscal quarter ending December 31, 2023, the Company will be subject to a financial covenant requiring it to achieve consolidated six months’ trailing revenues of at least 75% of its revenue plan for such period. The Loan Agreement includes customary events of defaults, including, among others, payment defaults, breach of representations and warrants, covenant defaults, cross-defaults to other debt, judgment defaults, insolvency and bankruptcy defaults, a material adverse change default and delisting of the Company’s common stock. The occurrence of an event of default could result in the acceleration of the obligations under the Loan Agreement, termination of the Term Loan commitments and the right to foreclose on the collateral securing the obligations. During the existence of an event of default, the Term Loans will accrue interest at a rate per annum equal to 5.0% above the otherwise applicable interest rate. The debt issuance costs were recorded as debt discounts and together with the final payment fee are being amortized using the effective interest rate method over the term of the loan. As of March 31, 2022, the effective interest rate on Term Loan A was 10.52% and the unamortized debt discount was $0.1 million. Amortization of the debt discount and accrual of final payment was approximately $17,000 for the three months ended March 31, 2022. Scheduled payments due under the Loan Agreement, excluding the final payment fee of $0.3 million and interest payments, are as follows: March 31, 2022 (in thousands) 2025 $ 2,174 2026 2,609 2027 217 Total $ 5,000 During the three months ended March 31, 2022, the Company recognized $0.1 million of interest expense related to the Loan Agreement. The Company did not incur interest expense for the three months ended March 31, 2021.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8 . Commitments and Contingencies Asset Purchase Agreement In August 2018, the Company entered into an Asset Purchase Agreement with Gilead whereby the Company acquired worldwide rights to the pharmaceutical product, momelotinib, an investigational orally bioavailable JAK1, JAK2 and ACVR1/ALK2 inhibitor together with all related intellectual property rights and certain other related assets. Pursuant to the agreement, the Company made a one-time upfront payment of $ 3.0 million in August 2018. In October 2019, the Company entered into an amendment to the Asset Purchase Agreement in which the Company agreed to issue, subject to certain conditions, shares of common stock and a warrant to purchase common stock to Gilead in consideration for meaningfully reduced royalty rates and elimination of a near term milestone payment in the Asset Purchase Agreement. Pursuant to the amended agreement, milestone payments of up to an aggregate of $ 190.0 million may become payable to Gilead upon the achievement of certain regulatory and commercial milestone events , including a milestone payment of $ 25.0 million due upon the approval of momelotinib from the U.S. Food and Drug Administration ( FDA ) . These milestones will be accrued once they are considered probable of occurring. In addition, the Company is now required to pay Gilead low double-digit to high-teens percent tiered combined royalties based upon net sales. License Agreements In August 2021, the Company entered into a license agreement with AstraZeneca for an exclusive global license for SRA515 and related compounds, which selectively inhibit BRD4. Under the agreement, the Company has an exclusive license to develop, manufacture and commercialize SRA515 for all therapeutic, prophylactic, palliative and diagnostic uses in humans and animals. T he Company made a one-time, non-refundable upfront cash payment of $8.0 million to AstraZeneca, which was expensed as research and development costs in 2021. Aggregate milestone payments of up to $208.0 million may become payable by the Company upon the achievement of certain development, regulatory and commercial milestones. In addition, the Company is required to pay AstraZeneca a tiered royalty on worldwide net sales ranging from high single-digits to low double-digits. In September 2016, the Company entered into an exclusive license agreement with CRT Pioneer Fund LP (CPF) for worldwide rights, know-how and materials to develop SRA737, a small molecule inhibitor targeting Chk1, a promising therapeutic target to treat cancer. Pursuant to the agreement, the Company made a one-time upfront payment of $7.0 million to CPF in October 2016 and paid $2.0 million to CPF in January 2017 for the successful transfer of two ongoing Phase 1 clinical trials. Pursuant to the original license agreement, additional milestone payments of up to an aggregate of $319.5 million may have become payable to CPF upon the achievement of certain milestones. In November 2020, the Company entered into an amendment to the license agreement with CPF, which amended the terms and reduced the amounts of certain future milestone payments. Pursuant to the amended agreement, future milestone payments of up to an aggregate of $290.0 million may become payable to CPF upon the achievement of certain developmental, regulatory and commercial milestones, including a milestone payment of $2.0 million upon the dosing of the first patient of the first trial of SRA737 by the Company following the effective date of the amendment. These milestones will be accrued once they are considered probable of occurring. In addition, the Company is required to pay CPF, on a product-by-product and country-by-country basis, tiered high single-digit to low double-digit royalties on the net sales of any product successfully developed. Legal From time to time, the Company may become subject to other legal proceedings, claims and litigation arising in the ordinary course of business. In addition, the Company may receive letters alleging infringement of patent or other intellectual property rights. The Company is not currently a party to any other material legal proceedings, nor is it aware of any pending or threatened litigation that, in the Company’s opinion, would have a material adverse effect on the business, operating results, cash flows or financial condition should such litigation be resolved unfavorably. COVID-19 The full extent of the impact of the COVID-19 pandemic on financial markets, economies worldwide and our business is highly uncertain. Research and development expenses and general and administrative expenses may vary significantly if there is an increased impact from COVID-19 on the costs and timing associated with the conduct of clinical trials and other related business activities. The Company is carefully monitoring the pandemic and the potential length and depth of the resulting economic impact on its financial condition and results of operations. As of March 31, 2022, the Company was not aware of any contingencies and no related estimates were recorded on its financial statements as a result of COVID-19.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Stockholders' Equity	9 . Underwritten Public Offering On January 31, 2022, the Company completed an underwritten public offering of 4,074,075 shares of common stock and pre-funded warrants to purchase up to 925,925 shares of common stock. As part of the underwritten public offering, on February 3, 2022, the Company issued an additional 750,000 shares of common stock representing the underwriters’ full exercise of their over-allotment option. The shares of common stock and the pre-funded warrants were offered by the Company at a price to the public of $27.00 and $26.999 per share, respectively. The aggregate net proceeds received by the Company from the offering were $145.3 million, net of underwriting discounts and commissions and offering expenses of $9.9 million. At-The-Market Common Stock Offering The Company filed prospectus supplements pursuant to which it can issue and sell an aggregate of up to $150.0 million of its common stock from time to time in At-The-Market (ATM) offerings. There were no ATM sales during the three months ended March 31, 2022. During the three months ended March 31, 2021, the Company sold 1,149,820 shares under the ATM program for net proceeds of $19.6 million, net of commissions and offering expenses Common Stock Reserved for Issuance The Company is required to reserve and keep available out of its authorized but unissued shares of common stock a number of shares sufficient to effect the conversion of all outstanding options granted and available for grant under the incentive plans, shares reserved for issuance under the employee stock purchase plan and issued warrants. March 31, 2022 December 31, 2021 Shares reserved under Series A warrant 7,771,951 7,790,879 Shares reserved under Series B warrant 212,477 2,524,732 Shares reserved for future option grants under equity plans 1,452,859 1,207,827 Outstanding stock options under equity incentive plans 5,466,822 4,937,189 Pre-funded warrants for common stock 925,925 — Outstanding warrants 1,839 727,122 Shares reserved under the 2015 employee stock purchase plan 17,500 17,500 Total common stock reserved for issuance 15,849,373 17,205,249 Common Stock Warrants In connection with the Company’s January 2022 public offering, the Company issued pre-funded warrants to purchase up to 925,925 shares of common stock. There were no pre-funded warrants exercised during the three months ended March 31, 2022. In connection with the Company’s November 2019 public offering, the Company issued Series A warrants to purchase up to 7,802,241 shares of common stock at an exercise price equal to $13.20, and Series B warrants to purchase up to 2,574,727 shares of common stock at an exercise price equal to $13.20. The Series A warrants will expire five years from the date they first became exercisable or on January 22, 2025 and contain a cash and/or cashless exercise provision. During the three months ended March 31, 2022, the Company issued 2,312,257 shares of common stock for the exercise of Series B warrants and 18,937 shares of common stock for the exercise of Series A warrants for proceeds of $30.5 million and $0.2 million, respectively. During the three months ended March 31, 2021, the Company issued 49,995 shares of common stock for the exercise of Series B warrants for proceeds of $0.7 million. See Note 12 for information pertaining to the exercise of Series A and Series B warrants subsequent to March 31, 2022. On September 8, 2021, the Company entered into Amendment No. 1 to Series A warrants and Amendment No. 1 to Series B warrants. These amendments clarified the methodology by which Series A warrants and Series B warrants would be assumed or settled in the event of a Fundamental Transaction, as defined under the warrant agreements, and provided for greater consistency in the treatment of these warrants by a publicly-traded or private buyer. The amendments did not result in changes to the fair value of these warrants. As such, no expense was recorded during 2021 relating to the modifications to the warrants. In connection with obligations under the amendment to the Asset Purchase Agreement (See Note 8), on January 31, 2020, the Company issued to Gilead 725,283 shares of the Company’s common stock and a warrant to purchase 725,283 shares of common stock at a price per share of $13.20. During the three months ended March 31, 2022, the warrant was fully exercised in cash by Gilead. Accordingly, the Company issued 725,283 shares of common stock for proceeds of $9.6 million. In August 2018, in connection with a Loan and Security Agreement (Loan Agreement) with Silicon Valley Bank (SVB), the Company issued a warrant to SVB to purchase 1,839 of the Company’s common stock at a price per share of $74.80. The warrant is immediately exercisable, will expire on August 21, 2028 and contains a cashless exercise provision.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	10 . In the accompanying condensed consolidated statements of operations, the Company recognized stock-based compensation expense for its employees and non-employees as follows: Three Months Ended March 31, 2022 2021 (in thousands) Research and development $ 1,594 $ 1,663 General and administrative 1,738 1,268 Total stock-based compensation $ 3,332 $ 2,931 Determination of Fair Value The fair values of the Company’s stock-based awards granted during the three months ended March 31, 2022 and 2021 were estimated as of the grant date using the Black-Scholes option pricing model, based on assumptions as follows: Three Months Ended March 31, 2022 2021 Expected term (in years) 6.0 – 6.1 5.5 – 7.0 Expected volatility 81 – 84 % 84 – 85 % Risk-free interest rate 1.5 – 2.1 % 0.5 – 1.1 % Expected dividend rate — % — % Equity Incentive Plans 2018 Equity Inducement Plan In September 2018, the Company’s Compensation Committee approved the 2018 Equity Inducement Plan (2018 Plan). The number of shares available for awards under the 2018 Plan was set to 37,500. In June 2020 and February 2021, amendments to the 2018 Plan were approved by the Company’s Board of Directors and Compensation Committee, respectively, each to increase the authorized number of shares available for issuance by 500,000 shares for an aggregate increase of 1,000,000 shares. On February 8, 2022, the Company’s Compensation Committee approved an amendment to the 2018 Plan to increase the authorized number of shares available for issuance by 500,000 shares. 2015 Plan The 2015 Equity Incentive Plan (2015 Plan) became effective on July 14, 2015. On January 21, 2020, the Company’s stockholders approved the following amendments to the 2015 Plan: (i) increase to the authorized number of shares available for issuance by 4,312,500 shares and proportionately increase the share limit related to incentive stock options, (ii) provide limits on the total value of compensation that may be granted to any non-employee director in each calendar year, and (iii) eliminate the annual individual grant limit to reflect changes to the tax law in 2017 tax legislation. As of March 31, 2022, 5,747,273 shares were reserved for issuance under the 2015 Plan. The number of shares reserved for issuance under the 2015 Plan will increase automatically on January 1 of each calendar year 2016 through 2025 by the number of shares equal to 4% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31. The Company’s Board of Directors or Compensation Committee may reduce the amount of the increase in any particular year. The exercise price of each stock-based award issued under the 2015 Plan is required to be no less than the fair value of the Company’s common stock. The vesting and exercise provisions of options or restricted awards granted are determined individually with each grant. Stock options have a 10-year life and expire if not exercised within that period or if not exercised within three months of cessation of employment with the Company or such longer period of time as specified in the option agreement, unless modified. 2008 Plan The Company granted options under the 2008 Stock Plan (2008 Plan) until July 2015 when it was terminated as to future awards, although it continues to govern the terms of options that remain outstanding under the 2008 Plan. The 2008 Plan provided for the granting of Incentive Stock Options (ISO), nonqualified stock options and stock purchase rights. In connection with the Board of Director’s approval of the 2015 Plan, all remaining shares available for future award under the 2008 Plan were transferred to the 2015 Plan, and the 2008 Plan was terminated. A summary of activity under the 2008 Plan, 2015 Plan and 2018 Plan and related information is as follows: Options Outstanding Shares Available for Grant Number of Shares Outstanding Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value of Outstanding Options (in thousands) Outstanding — December 31, 2021 1,207,827 4,937,189 $ 19.23 8.14 $ 36,080 Awards authorized 1,122,866 Options granted (995,380 ) 995,380 30.87 Options exercised — (348,201 ) 13.13 Options forfeited/cancelled 117,546 (117,546 ) 22.36 Outstanding — March 31, 2022 1,452,859 5,466,822 $ 21.67 8.37 $ 76,739 Exercisable — March 31, 2022 1,625,633 $ 28.54 7.28 $ 25,331 Vested and expected to vest — March 31, 2022 4,957,332 $ 22.65 8.40 $ 66,600 The weighted-average grant date fair values of options granted during the three months ended March 31, 2022 was $22.06 per share, and $11.73 per share for the three months ended March 31, 2021. The aggregate intrinsic value of options exercised was $5.0 million and $0.1 million for the three months ended March 31, 2022 and 2021. The total grant date fair value of options vested for the three months ended March 31, 2022 and 2021 was $5.7 million, and $3.4 million, respectively. In August 2020, the Company granted executives and employees 1,107,250 stock options with performance-based conditions. Vesting is achieved based upon the completion of pre-determined milestones. During the three months ended March 31, 2022, the first performance-based milestone was met, and accordingly, 257,255 of the performance-based options vested. For the three months ended March 31, 2022, the Company recognized approximately $0.5 million in stock-based compensation expense (including the modification described below) related to the options with performance-based criteria. On March 22, 2022, the Company entered into a transition agreement with the Company’s former Chief, Research and Early Development. Pursuant to the transition agreement, the former executive’s time-based options will be considered to have vested only up to March 10, 2022 (Termination Date), and the portion of each time-based option that was unvested as of the Termination Date were cancelled. The former executive received an extension of the expiration date of his vested stock options through a consulting period while he remains in service to the Company. Furthermore, his performance-based options will continue to vest through the consulting period. All performance options that remain unvested following the termination of the consulting period will be cancelled. Compensation costs relating to the modifications to option terms was $0.4 million, of which $0.3 million relates to modification of stock options with performance-based conditions for three months ended March 31, 2022. As of March 31, 2022, total unrecognized stock-based compensation related to unvested stock options with only service-vesting conditions was $43.4 million and are expected to be recognized over a remaining weighted-average period of 3.2 years. As of March 31, 2022, total unrecognized stock-based compensation related to unvested stock options with performance-based conditions was $4.7 million.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	1 1 . The Company did not record a provision for U.S. federal income taxes for the three months ended March 31, 2022 because it expects to generate a loss for the year ended December 31, 2022. The income tax provision for (benefit from) for the three months ended March 31, 2022 and 2021 represented foreign taxes. The Company’s net U.S. deferred tax assets continue to be offset by a full valuation allowance. Utilization of the Company’s net operating loss and U.S. research and development credit carryforwards to offset taxable income are subject to an annual limitation, pursuant to Internal Revenue Code (IRC) Sections 382 and 383. As a result of common stock issuances and changes in the stock ownership that occurred subsequent to 2019, an ownership change under Section 382 is deemed to have occurred during the first quarter of 2022. As such, certain of the Company’s tax attributes existing as of the date of the ownership changes may not be available for future use. The loss or ultimate limitation of these attributes will not have any impact on the financial statements since the net U.S. deferred tax assets are offset by a full valuation allowance.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	12. Subsequent Events Proposed Merger with GlaxoSmithKline On April 12, 2022, the Company entered into a Merger Agreement as further described in Note 1. For additional information regarding the Merger, please refer to the Merger Agreement, which was filed with the SEC on April 13, 2022, as an exhibit to a Current Report on Form 8-K. Common Stock Issuances In April 2022, the Company issued 212,477 shares of common stock for the exercise of Series B Warrants for proceeds of $2.8 million prior to their expiration on April 10, 2022. In April 2022, the Company issued 7,575 shares of common stock for the cash exercise of Series A Warrants for proceeds of $0.1 million. In addition, 373,606 shares of common stock were issued for the cashless exercise of Series A Warrants. In April 2022, the Company issued 25,282 shares of common stock in connection with the exercise of stock options under pre-established non-discretionary sales plans and by a former employee for proceeds of $0.3 million.

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 The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and applicable rules and regulations of the Securities and Exchange Commission (SEC) regarding interim financial reporting. Accordingly, they do not include all the information and notes required for complete financial statements and should be read in conjunction with the Company’s audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, filed with the SEC on March 10, 2022. There were no significant changes to the accounting policies during the three months ended March 31, 2022 from the significant accounting policies described in Note 2 to the consolidated financial statements in the 2021 Form 10-K. The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. These unaudited condensed consolidated financial statements and related disclosure have been prepared on the same basis as the annual consolidated financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s condensed consolidated financial statements included in this report. The condensed consolidated results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the year ending December 31, 2022 , or for any other future annual or interim period. The condensed consolidated balance sheet as of December 31, 2021 included herein was derived from the audited consolidated financial statements as of that date.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of expense during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to the fair value of stock options issued, the probability of achieving performance-based milestones of stock options, accruals such as research and development costs, and recoverability of the Company’s net deferred tax assets and related valuation allowance. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates.

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Schedule of Outstanding Shares of Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share	The following shares of common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented because including them would have been antidilutive: March 31, 2022 March 31, 2021 Series A warrants for common stock 7,771,951 7,802,241 Series B warrants for common stock 212,477 2,524,732 Options to purchase common stock 5,466,822 4,667,173 Pre-funded warrants for common stock 925,925 — Warrants for common stock 1,839 727,122 Total potential dilutive shares 14,379,014 15,721,268

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Fair Value Assets And Liabilities Measured On Recurring Basis	The following table sets forth the fair value of the Company’s financial assets measured on a recurring basis by level within the fair value hierarchy: March 31, 2022 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 271,564 $ — $ — $ 271,564 December 31, 2021 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 102,526 $ — $ — $ 102,526

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Cash and Cash Equivalents	Cash and cash equivalents consist of the following: March 31, 2022 December 31, 2021 (in thousands) Cash $ 2,451 $ 2,223 Cash equivalents: Money market accounts 271,564 102,526 Total cash and cash equivalents $ 274,015 $ 104,749
Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the condensed consolidated balance sheets to the amounts shown in the condensed consolidated statements of cash flows. March 31, 2022 March 31, 2021 (in thousands) Cash and cash equivalents $ 274,015 $ 107,658 Restricted cash included in other assets 300 300 Total cash, cash equivalents and restricted cash shown in the condensed consolidated statement of cash flows $ 274,315 $ 107,958
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following: March 31, 2022 December 31, 2021 (in thousands) Prepaid research and development project costs $ 1,233 $ 290 Prepaid software and subscription fees 1,130 536 Prepaid insurance 556 1,029 Other receivables 270 147 Other 993 642 Total prepaid expenses and other current assets $ 4,182 $ 2,644
Summary of Property and Equipment, Net	Property and equipment, net consists of the following: March 31, 2022 December 31, 2021 (in thousands) Software $ 456 $ 456 Leasehold improvements 35 35 Computer equipment 5 5 Property and equipment, gross 496 496 Less: accumulated depreciation (367 ) (355 ) Total property and equipment, net $ 129 $ 141
Schedule of Accrued and Other Liabilities	Accrued and other liabilities consist of the following: March 31, 2022 December 31, 2021 (in thousands) Accrued research and development costs $ 4,864 $ 2,727 Accrued employee related costs 3,383 6,725 Accrued professional fees 2,427 739 Operating lease liabilities 318 368 Other 290 167 Total accrued and other liabilities $ 11,282 $ 10,726

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Schedule of Components of Lease Expense and Related Cash Flows	The components of lease expense and related cash flows for the three months ended March 31, 2022 and 2021 were as follows: Three Months Ended March 31, 2022 2021 (in thousands) Operating lease cost $ 89 $ 43 Short-term lease cost $ 7 7 96 50 Operating cash flows used for operating leases $ 110 $ 57
Schedule of Maturities Lease Liabilities under Leases Agreements	As of March 31, 2022, maturities of lease liability due under the lease agreements are as follows: Years Ending December 31: Operating Leases (in thousands) Remainder of 2022 289 2023 223 2024 230 2025 58 Total lease payments 800 Less imputed interest (46 ) Total 754

Term Loan (Tables)

Term Loan (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Schedule of Payments Due Under Loan Agreement	Scheduled payments due under the Loan Agreement, excluding the final payment fee of $0.3 million and interest payments, are as follows: March 31, 2022 (in thousands) 2025 $ 2,174 2026 2,609 2027 217 Total $ 5,000

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Schedule of Common Stock Reserved for Issuance	The Company is required to reserve and keep available out of its authorized but unissued shares of common stock a number of shares sufficient to effect the conversion of all outstanding options granted and available for grant under the incentive plans, shares reserved for issuance under the employee stock purchase plan and issued warrants. March 31, 2022 December 31, 2021 Shares reserved under Series A warrant 7,771,951 7,790,879 Shares reserved under Series B warrant 212,477 2,524,732 Shares reserved for future option grants under equity plans 1,452,859 1,207,827 Outstanding stock options under equity incentive plans 5,466,822 4,937,189 Pre-funded warrants for common stock 925,925 — Outstanding warrants 1,839 727,122 Shares reserved under the 2015 employee stock purchase plan 17,500 17,500 Total common stock reserved for issuance 15,849,373 17,205,249

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock-based Compensation Expense for Employees and Non-employees	In the accompanying condensed consolidated statements of operations, the Company recognized stock-based compensation expense for its employees and non-employees as follows: Three Months Ended March 31, 2022 2021 (in thousands) Research and development $ 1,594 $ 1,663 General and administrative 1,738 1,268 Total stock-based compensation $ 3,332 $ 2,931
Schedule of Estimated Grant-date Fair Value of Stock-based Awards Using Black-Scholes Option Pricing Model Assumptions	The fair values of the Company’s stock-based awards granted during the three months ended March 31, 2022 and 2021 were estimated as of the grant date using the Black-Scholes option pricing model, based on assumptions as follows: Three Months Ended March 31, 2022 2021 Expected term (in years) 6.0 – 6.1 5.5 – 7.0 Expected volatility 81 – 84 % 84 – 85 % Risk-free interest rate 1.5 – 2.1 % 0.5 – 1.1 % Expected dividend rate — % — %
Summary of Stock-Based Compensation Activity	A summary of activity under the 2008 Plan, 2015 Plan and 2018 Plan and related information is as follows: Options Outstanding Shares Available for Grant Number of Shares Outstanding Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value of Outstanding Options (in thousands) Outstanding — December 31, 2021 1,207,827 4,937,189 $ 19.23 8.14 $ 36,080 Awards authorized 1,122,866 Options granted (995,380 ) 995,380 30.87 Options exercised — (348,201 ) 13.13 Options forfeited/cancelled 117,546 (117,546 ) 22.36 Outstanding — March 31, 2022 1,452,859 5,466,822 $ 21.67 8.37 $ 76,739 Exercisable — March 31, 2022 1,625,633 $ 28.54 7.28 $ 25,331 Vested and expected to vest — March 31, 2022 4,957,332 $ 22.65 8.40 $ 66,600

Organization - Additional Infor

Organization - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Apr. 12, 2022	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Organization [Line Items]
Cash and cash equivalents		$ 274,015	$ 104,749	$ 107,658
GlaxoSmithKline [Member] | Subsequent Event [Member]
Organization [Line Items]
Right to receive cash without interest per share	$ 55
Termination fee	$ 70,000

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Outstanding Shares of Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential dilutive shares	14,379,014	15,721,268
Series A Warrants For Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential dilutive shares	7,771,951	7,802,241
Series B Warrants For Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential dilutive shares	212,477	2,524,732
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential dilutive shares	5,466,822	4,667,173
Pre funded Warrants for Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential dilutive shares	925,925
Warrants for Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potential dilutive shares	1,839	727,122

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value of Financial Assets Measured on Recurring Basis (Detail) - Fair Value Measurements Recurring [Member] - Money Market Funds [Member] - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial Assets
Total financial assets	$ 271,564	$ 102,526
Level 1 [Member]
Financial Assets
Total financial assets	$ 271,564	$ 102,526

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Cash And Cash Equivalents [Abstract]
Cash	$ 2,451	$ 2,223
Cash equivalents:
Money market accounts	271,564	102,526
Total cash and cash equivalents	$ 274,015	$ 104,749	$ 107,658

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 274,015	$ 104,749	$ 107,658
Restricted cash included in other assets	300		300
Total cash, cash equivalents and restricted cash shown in the condensed consolidated statement of cash flows	$ 274,315	$ 105,049	$ 107,958	$ 104,355

Balance Sheet Components - Su_3

Balance Sheet Components - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid research and development project costs	$ 1,233	$ 290
Prepaid software and subscription fees	1,130	536
Prepaid insurance	556	1,029
Other receivables	270	147
Other	993	642
Total prepaid expenses and other current assets	$ 4,182	$ 2,644

Balance Sheet Components - Su_4

Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 496	$ 496
Less: accumulated depreciation	(367)	(355)
Total property and equipment, net	129	141
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	456	456
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	35	35
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 5	$ 5

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Property Plant And Equipment [Abstract]
Depreciation	$ 12,000	$ 10,000

Balance Sheet Components - Su_5

Balance Sheet Components - Summary of Accrued and Other Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables And Accruals [Abstract]
Accrued research and development costs	$ 4,864	$ 2,727
Accrued employee related costs	3,383	6,725
Accrued professional fees	2,427	739
Operating lease liabilities	$ 318	$ 368
Operating Lease Liability Current Statement Of Financial Position Extensible List	Accrued and other liabilities	Accrued and other liabilities
Other	$ 290	$ 167
Total accrued and other liabilities	$ 11,282	$ 10,726

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2020
California [Member]
Loss Contingencies [Line Items]
Operating lease agreement term		48 months
Operating lease agreement expiration date	Apr. 30, 2025
Vancouver [Member]
Loss Contingencies [Line Items]
Operating lease agreement expiration date	Feb. 28, 2023
Annual sublease base rent	$ 0.2
Weighted-average remaining lease term, operating leases (Year)	2 years 8 months 12 days
Weighted-average discount rate, Operating leases	4.60%
Future sublease base rent	$ 0.2

Leases - Schedule of Components

Leases - Schedule of Components of Lease Expense and Related Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Leases [Abstract]
Operating lease cost	$ 89	$ 43
Short-term lease cost	7	7
Total Lease Cost	96	50
Operating cash flows used for operating leases	$ 110	$ 57

Leases - Schedule of Maturities

Leases - Schedule of Maturities Lease Liabilities under Leases Agreements (Detail) $ in Thousands	Mar. 31, 2022USD ($)
Leases [Abstract]
Remainder of 2022	$ 289
2023	223
2024	230
2025	58
Total lease payments	800
Less imputed interest	(46)
Total	$ 754

Term Loan - Additional Informat

Term Loan - Additional Information (Detail) - Oxford Finance, LLC [Member]	Jan. 21, 2022USD ($)Tranche	Dec. 31, 2023	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)
Debt Instrument [Line Items]
Aggregate principal amount of loan	$ 125,000,000
Number of tranches | Tranche	4
Loan agreement, description			Contemporaneously with executing the Loan Agreement, the Company drew down the first $5.0 million tranche (Term Loan A).
Proceeds from issuance of debt			$ 5,000,000
Floating interest per annum	5.25%
Interest rate, stated percentage			8.50%
Payment term			Beginning (i) March 1, 2025, if either the Term B Loan or the Term C Loan is not made or (ii) September 1, 2025, if both the Term B Loan and the Term C Loan are made, the Company shall repay the Term Loans in consecutive equal monthly payments of principal, together with applicable interest, in arrears. All unpaid principal and accrued and unpaid interest with respect to each Term Loan is due and payable in full on January 1, 2027
Maturity date	Jan. 1, 2027
Final payment fee	6.00%
Facility fee	0.50%
Term loan covenant terms description	The Loan Agreement contains customary affirmative and restrictive covenants, including, among others, covenants restricting the Company from incurring additional indebtedness, granting liens, making investments, consummating transactions with affiliates, disposing of assets, consummating mergers or acquisitions, having a change of control and paying dividends or distributions, subject in each case, to customary qualifications and exceptions. In addition, beginning with the fiscal quarter ending December 31, 2023, the Company will be subject to a financial covenant requiring it to achieve consolidated six months’ trailing revenues of at least 75% of its revenue plan for such period.
Percentage of default accrued interest rate per annum	5.00%
Final payment fee			$ 300,000
Interest expense			$ 100,000	$ 0
Minimum [Member]
Debt Instrument [Line Items]
Aggregate outstanding principal amount of the term loans	$ 50,000,000
Minimum [Member] | Scenario Forecast [Member]
Debt Instrument [Line Items]
Percentage of trailing revenues		75.00%
Before First Anniversary [Member]
Debt Instrument [Line Items]
Accrued interest and the final payment fee subject to a prepayment fee	2.00%
After First and Before Third Anniversary [Member]
Debt Instrument [Line Items]
Accrued interest and the final payment fee subject to a prepayment fee	1.00%
Floor Rate [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	8.50%
Term Loan A [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 5,000,000
Effective interest rate of loan			10.52%
Unamortized debt discount			$ 100,000
Amortization of debt discount and accrual of final payment			$ 17,000
Term Loan C [Member]
Debt Instrument [Line Items]
Aggregate principal amount of loan	$ 70,000,000
Line of credit facility expiration period	30 days
Line of credit facility expiration date	Dec. 31, 2023
Term Loan D [Member]
Debt Instrument [Line Items]
Aggregate principal amount of loan	$ 50,000,000

Term Loan - Schedule of Payment

Term Loan - Schedule of Payments Due Under Loan Agreement (Detail) - Oxford Finance, LLC [Member] $ in Thousands	Mar. 31, 2022USD ($)
Debt Instrument [Line Items]
2025	$ 2,174
2026	2,609
2027	217
Total	$ 5,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended			3 Months Ended
	Aug. 31, 2021	Aug. 31, 2018	Oct. 31, 2016	Mar. 31, 2022	Nov. 30, 2020	Jan. 31, 2017
Asset Purchase Agreement [Member]
Loss Contingencies [Line Items]
Upfront payment paid		$ 3
Aggregate milestone payment				$ 190
Asset Purchase Agreement [Member] | Approval from FDA [Member]
Loss Contingencies [Line Items]
Milestone payment				25
AstraZeneca License Agreement [Member]
Loss Contingencies [Line Items]
Aggregate milestone payment	$ 208
Upfront payment	$ 8
CPF License Agreements [Member]
Loss Contingencies [Line Items]
Upfront payment			$ 7
Additional milestone payment payable				319.5
CPF License Agreements [Member] | Transfer of Phase 1 Clinical Trials [Member]
Loss Contingencies [Line Items]
Milestone payment						$ 2
CPF License Agreements [Member] | First patient first trial post amendment [Member]
Loss Contingencies [Line Items]
Milestone payment					$ 2
CPF License Agreement Amendment [Member]
Loss Contingencies [Line Items]
Additional milestone payment payable				$ 290

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Feb. 03, 2022	Jan. 31, 2022	Jan. 31, 2020	Aug. 31, 2018	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Nov. 30, 2021	Nov. 30, 2019
Class Of Stock [Line Items]
Proceeds from warrant exercises					$ 40,346,000	$ 660,000
Expense relating to the modifications to warrants							$ 0
Silicon Valley Bank [Member] | Term Loans [Member] | Warrants [Member]
Class Of Stock [Line Items]
Exercise price of warrants or rights				$ 74.80
Warrant expiration date				Aug. 21, 2028
Warrants issued in connection with loan				1,839
Asset Purchase Agreement Amendment [Member] | Gilead [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares			725,283
Number of securities called by warrants and rights			725,283
Exercise price of warrants or rights			$ 13.20
Issuance of common stock for exercise of common stock warrant, Shares					725,283
Proceeds from warrant exercises					$ 9,600,000
Series A Warrants [Member]
Class Of Stock [Line Items]
Number of securities called by warrants and rights									7,802,241
Exercise price of warrants or rights									$ 13.20
Warrant expiration date					Jan. 22, 2025
Issuance of common stock for exercise of common stock warrant, Shares					18,937
Proceeds from warrant exercises					$ 200,000
Series B Warrants [Member]
Class Of Stock [Line Items]
Number of securities called by warrants and rights									2,574,727
Exercise price of warrants or rights									$ 13.20
Issuance of common stock for exercise of common stock warrant, Shares					2,312,257	49,995
Proceeds from warrant exercises					$ 30,500,000	$ 700,000
Common Stock [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares					4,824,075	1,149,820
Issuance of common stock for exercise of common stock warrant, Shares					3,056,477	49,995
Underwritten Public Offering [Member]
Class Of Stock [Line Items]
Proceeds from issuance of common stock, net of deferred financing costs		$ 145,300,000
Underwriting discounts and commissions and offering expenses		$ 9,900,000
Underwritten Public Offering [Member] | Common Stock [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares	750,000	4,074,075
Share issued price per share		$ 27
Underwritten Public Offering [Member] | Warrants [Member]
Class Of Stock [Line Items]
Number of securities called by warrants and rights		925,925
Share issued price per share		$ 26.999
At-The-Market Offering [Member]
Class Of Stock [Line Items]
Issuance of common stock, Shares					0	1,149,820
Proceeds from issuance of common stock, net of offering costs						$ 19,600,000
Authorized stock issuance value remaining capacity					$ 59,600,000
At-The-Market Offering [Member] | Maximum [Member]
Class Of Stock [Line Items]
Common stock reserved for issuance								$ 150,000,000

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Common Stock Reserved for Issuance (Detail) - shares	Mar. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Total common stock reserved for future issuance	15,849,373	17,205,249
Series A Warrants [Member]
Class Of Stock [Line Items]
Total common stock reserved for future issuance	7,771,951	7,790,879
Series B Warrants [Member]
Class Of Stock [Line Items]
Total common stock reserved for future issuance	212,477	2,524,732
Equity Incentive Plans [Member]
Class Of Stock [Line Items]
Total common stock reserved for future issuance	1,452,859	1,207,827
Awards outstanding	5,466,822	4,937,189
2015 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Total common stock reserved for future issuance	17,500	17,500
Warrants to Purchase Common Stock [Member]
Class Of Stock [Line Items]
Outstanding warrants	1,839	727,122
Underwritten Public Offering [Member] | Pre-funded Warrants to Purchase Common Stock [Member]
Class Of Stock [Line Items]
Total common stock reserved for future issuance	925,925

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-based Compensation Expense for Employees and Non-employees (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 3,332	$ 2,931
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	1,594	1,663
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 1,738	$ 1,268

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Estimated Grant-date Fair Values of Stock-based Awards Using Black-Scholes Option Pricing Model Assumptions (Detail)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, Minimum	81.00%	84.00%
Expected volatility, Maximum	84.00%	85.00%
Risk-free interest rate, Minimum	1.50%	0.50%
Risk-free interest rate, Maximum	2.10%	1.10%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years	5 years 6 months
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	7 years

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Feb. 08, 2022	Jan. 21, 2020	Aug. 31, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021	Feb. 28, 2021	Sep. 30, 2021	Dec. 31, 2021	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares reserved for issuance					15,849,373				17,205,249
Total stock-based compensation					$ 3,332	$ 2,931
Share Based Compensation Arrangement Modification [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs relating to vesting acceleration and modification					400
Contract Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs relating to vesting acceleration and modification					$ 300
Performance Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Executives and employees stock options granted			1,107,250
Options vested					257,255
Total stock-based compensation					$ 500	$ 800
Total unrecognized stock-based compensation related to unvested stock options					4,700
Service Vesting Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock-based compensation related to unvested stock options					$ 43,400
Weighted-average period								3 years 2 months 12 days
2018 Equity Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares reserved for issuance					1,037,500					37,500
Common shares authorized to be issued during the period	500,000			500,000			1,000,000
Stock option life in years					10 years
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares reserved for issuance					5,747,273
Common shares authorized to be issued during the period		4,312,500
Stock option life in years					10 years
Percentage threshold of outstanding shares increased annually under the plan					4.00%
Stock option grants description					the number of shares equal to 4% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31.
2008 Plan, 2015 Plan and 2018 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized to be issued during the period					1,122,866
Weighted-average grant date fair values of options granted					$ 22.06	$ 11.73
Aggregate intrinsic value of options exercised					$ 5,000	$ 100
Total grant date fair value of options vested					$ 5,700	$ 3,400

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Activity (Detail) - 2008 Plan, 2015 Plan and 2018 Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Options Outstanding, Shares Available for Grant
Shares Available for Grant, Beginning balance	1,207,827
Shares Available for Grant, Awards authorized	1,122,866
Shares Available for Grant, Granted	(995,380)
Shares Available for Grant, forfeited/cancelled	117,546
Shares Available for Grant, Ending balance	1,452,859	1,207,827
Options Outstanding, Number of Shares Outstanding
Number of Shares Outstanding, Beginning balance	4,937,189
Number of Shares Outstanding, Options granted	995,380
Number of Shares Outstanding, Options exercised	(348,201)
Number of Shares Outstanding, Options forfeited/cancelled	(117,546)
Number of Shares Outstanding, Ending balance	5,466,822	4,937,189
Number of Shares Outstanding, Exercisable	1,625,633
Number of Shares Outstanding, Vested and expected to vest	4,957,332
Options Outstanding, Weighted-Average Exercise Price Per Share
Weighted-Average Exercise Price Per Share, Beginning balance	$ 19.23
Weighted-Average Exercise Price Per Share, Options granted	30.87
Weighted-Average Exercise Price Per Share, Options exercised	13.13
Weighted-Average Exercise Price Per Share, Options forfeited/cancelled	22.36
Weighted-Average Exercise Price Per Share, Ending balance	21.67	$ 19.23
Weighted-Average Exercise Price Per Share, Exercisable	28.54
Weighted-Average Exercise Price Per Share, Vested and expected to vest	$ 22.65
Options Outstanding, Weighted-Average Remaining Contractual Term (Years)
Weighted-Average Remaining Contractual Term (Years)	8 years 4 months 13 days	8 years 1 month 20 days
Weighted-Average Remaining Contractual Term (Year), Exercisable	7 years 3 months 10 days
Weighted-Average Remaining Contractual Term (Year), Vested and expected to vest	8 years 4 months 24 days
Options Outstanding, Aggregate Intrinsic Value of Outstanding Options
Aggregate Intrinsic Value of Outstanding Options	$ 76,739	$ 36,080
Aggregate Intrinsic Value of Outstanding Options, Exercisable	25,331
Aggregate Intrinsic Value of Outstanding Options, Vested and expected to vest	$ 66,600

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2022USD ($)
Income Tax Disclosure [Abstract]
Federal income tax provision, continuing operations	$ 0

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2022	Mar. 31, 2022	Mar. 31, 2021
Subsequent Event [Line Items]
Proceeds from exercise of common stock warrants		$ 40,346	$ 660
Proceeds from exercise of common stock options		$ 4,572	$ 288
Subsequent Event [Member] | Former Employees and Non-discretionary Sales [Member]
Subsequent Event [Line Items]
Issuance of common stock for exercise of common stock options, Shares	25,282
Proceeds from exercise of common stock options	$ 300
Subsequent Event [Member] | Series A Warrants [Member]
Subsequent Event [Line Items]
Issuance of common stock for exercise of common stock warrant, Shares	7,575
Proceeds from exercise of common stock warrants	$ 100
Issuance of common stock pertaining to cashless warrant exercise	373,606
Series B Warrants [Member]
Subsequent Event [Line Items]
Issuance of common stock for exercise of common stock warrant, Shares		2,312,257	49,995
Proceeds from exercise of common stock warrants		$ 30,500	$ 700
Series B Warrants [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Issuance of common stock for exercise of common stock warrant, Shares	212,477
Proceeds from exercise of common stock warrants	$ 2,800