Viracta Therapeutics (VIRX) 10-Q 10 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	VIRACTA THERAPEUTICS, INC.
Entity Central Index Key	0001061027
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		37,488,274
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Entity File Number	000-51531
Entity Tax Identification Number	94-3295878
Entity Address, Address Line One	2533 S. Coast Hwy. 101, Suite 210
Entity Address, City or Town	Cardiff
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92007
City Area Code	858
Local Phone Number	400-8470
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Trading Symbol	VIRX
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 92,199,000	$ 103,554,000
Prepaid expenses and other current assets	3,174,000	1,719,000
Total current assets	95,373,000	105,273,000
Property and equipment, net	210,000	242,000
Operating lease right-of-use asset	549,000	640,000
Other assets	2,255,000	2,397,000
Total assets	98,387,000	108,552,000
Current Liabilities:
Accounts payable	3,222,000	2,901,000
Accrued expenses	4,152,000	5,802,000
Operating lease liability	392,000	381,000
Total current liabilities	7,766,000	9,084,000
Long-term debt, net	4,841,000	4,819,000
Operating lease liabilities, less current portion	175,000	278,000
Stockholders' equity (deficit):
Convertible preferred stock, $0.0001 par value; 10,000,000 shares authorized as of March 31, 2022; 10,248 shares issued and outstanding as of March 31, 2022 and December 31, 2021	5,452,000	5,452,000
Common stock, $0.0001 par value; 400,000,000 shares authorized; 37,486,177 and 37,424,863 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	4,000	4,000
Additional paid-in capital	256,372,000	254,592,000
Accumulated deficit	(176,223,000)	(165,677,000)
Total stockholders' equity (deficit)	85,605,000	94,371,000
Total liabilities and stockholders' equity (deficit)	$ 98,387,000	$ 108,552,000

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Preferred stock, par value	$ 0.0001
Preferred stock, shares authorized	10,000,000
Preferred stock, shares issued	10,248	10,248
Preferred stock, shares outstanding	10,248	10,248
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	37,486,177	37,424,863
Common stock, shares outstanding	37,486,177	37,424,863

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses:
Research and development	$ 6,096	$ 4,024
Acquired in-process research and development	0	84,478
General and administrative	4,336	3,840
Total operating expenses	10,432	92,342
Gain on Royalty Purchase Agreement	0	13,500
Loss from operations	(10,432)	(78,842)
Other income (expense)
Interest income	10	6
Interest expense	(124)	(105)
Other expense	0	(290)
Total other expense	(114)	(389)
Net loss and comprehensive loss	$ (10,546)	$ (79,231)
Net loss per share of common stock, basic and diluted	$ (0.28)	$ (5.22)
Weighted-average shares used to compute basic and diluted net loss per share	37,535,874	15,166,737

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Preferred Stock [Member]	Preferred Stock [Member]Series A-1 Convertible Preferred Stock [Member]	Preferred Stock [Member]Series B Convertible Preferred Stock [Member]	Preferred Stock [Member]Series C Convertible Preferred Stock [Member]	Preferred Stock [Member]Series D Convertible Preferred Stock [Member]	Preferred Stock [Member]Series E Convertible Preferred Stock [Member]	Preferred Stock [Member]Convertible preferred stock	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2020	$ (46,200)	$ 1		$ 2,968	$ 15,484	$ 9,392	$ 16,589	$ 38,869		$ 4,714	$ (50,915)
Beginning Balance, shares at Dec. 31, 2020		906,000		4,819,000	2,788,000	1,588,000	2,224,000	7,392,000
Exercise of warrants and stock options to purchase common stock	81									81
Exercise of warrants and stock options to purchase common stock, shares		132,000
Vesting of early exercise of stock options, shares		1,000
Vesting of early exercise of stock options,Value	1									1
Issuance of common stock net of issuance costs	62,317	$ 1								62,316
Issuance of common stock net of issuance costs, shares		12,012,000
Issuance of common stock to fomer stockholders of Sunesis upon Merger	97,982									97,982
Issuance of common stock to fomer stockholders of Sunesis upon Merger, shares		5,173,000
Conversion of convertible preferred stock into common stock upon Merger	83,302	$ 2		$ (2,968)	$ (15,484)	$ (9,392)	$ (16,589)	$ (38,869)		83,300
Conversion of convertible preferred stock into common stock upon Merger, shares		18,812,000		(4,819,000)	(2,788,000)	(1,588,000)	(2,224,000)	(7,392,000)
Reclassification of preferred stock warrant liability to equity	396									396
Issuance of convertible preferred stock to former stockholders of Sunesis upon Merger	5,452								$ 5,452
Issuance of convertible preferred stock to former stockholders of Sunesis upon Merger, shares									10,000
Share-based compensation expense	644									644
Net loss	(79,231)										(79,231)
Ending Balance at Mar. 31, 2021	124,744	$ 4							$ 5,452	249,434	(130,146)
Ending Balance, shares at Mar. 31, 2021		37,036,000							10,000
Beginning Balance at Dec. 31, 2021	94,371	$ 4	$ 5,452							254,592	(165,677)
Beginning Balance, shares at Dec. 31, 2021		37,425	10
Exercise of warrants and stock options to purchase common stock	$ 7									$ 7
Exercise of warrants and stock options to purchase common stock, shares	7,000	7
Vesting of early exercise of stock options, shares	1	1								1
Vesting of restricted stock units, shares		53
Share-based compensation expense	$ 1,772									$ 1,772
Net loss	(10,546)										(10,546)
Ending Balance at Mar. 31, 2022	$ 85,605	$ 4	$ 5,452							$ 256,372	$ (176,223)
Ending Balance, shares at Mar. 31, 2022	0	37,486	10

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net loss	$ (10,546)	$ (79,231)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Acquired in-process research and development	0	84,478
Share-based compensation expense	1,772	644
Depreciation and amortization	54	16
Change in fair value of preferred stock warrant liability	0	290
Change in operating assets and liabilities:
Prepaid expenses and other assets	(1,455)	(2,447)
Other assets	142	455
Accounts payable	321	(409)
Accrued expenses	(1,650)	(1,250)
Lease liabilities, net	(1)	5
Net cash (used in) provided by operating activities	(11,363)	2,551
Investing activities
Cash acquired in connection with the Merger	0	17,143
Net cash provided by investing activities	0	17,143
Financing activities
Issuance of common stock, net of issuance costs	1	62,317
Exercise of warrants and stock options to purchase common stock	7	81
Net cash provided by financing activities	8	62,398
Net increase (decrease) in cash and cash equivalents	(11,355)	82,092
Cash and cash equivalents at beginning of period	103,554	47,089
Cash and cash equivalents at end of period	92,199	129,181
Supplemental disclosure of cash flow information
Interest paid	102	84
Noncash financing activities
Warrant liability reclassification to equity	0	396
Issuance of convertible preferred stock upon merger	0	5,452
Conversion of convertible preferred stock into common stock upon Merger	0	83,302
Issuance of common stock upon Merger	$ 0	$ 97,982

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Viracta Therapeutics, Inc. (“Viracta,” the “Company,” or the “combined company”), formerly known as Sunesis Pharmaceuticals, Inc., was incorporated in the state of Delaware in February 1998 and is based in San Diego, California. Viracta is a precision oncology company, focused on the development of new medicines targeting virus-associated malignancies. Viracta’s lead product candidate is an all-oral combination therapy of its proprietary investigational drug, nanatinostat and the antiviral agent valganciclovir (collectively referred to as “Nana-val”). Nana-val is currently being investigated in multiple ongoing clinical trials, including NAVAL-1, a pivotal, global, multicenter, open-label Phase 2 basket trial for the treatment of multiple subtypes of relapsed/refractory (“R/R”) Epstein-Barr virus-positive (“EBV + ”) lymphoma, as well as a multinational, open-label Phase 1b/2 trial for the treatment of EBV + recurrent or metastatic nasopharyngeal carcinoma (“R/M NPC”) and other EBV + solid tumors. The Company is also pursuing the application of its inducible synthetic lethality approach in other virus-related cancers. Merger Transaction between Private Viracta Therapeutics, Inc. and Sunesis Pharmaceuticals, Inc. and Name Change On November 29, 2020, the Company, then operating as Sunesis Pharmaceuticals, Inc., entered into an agreement and plan of merger and reorganization (the “Merger Agreement”) with privately-held Viracta Therapeutics, Inc. (“Private Viracta”) and Sol Merger Sub, Inc., a wholly-owned subsidiary of the Company (“Merger Sub”). On February 24, 2021, the transactions contemplated by the Merger Agreement were completed, and Merger Sub merged into Private Viracta, with Private Viracta surviving the merger as a wholly owned subsidiary of the Company (the “Merger”). Sunesis changed its name to Viracta Therapeutics, Inc. On February 25, 2021, the combined company’s common stock began trading on The Nasdaq Global Select Market under the ticker symbol “VIRX”. Except as otherwise indicated, references herein to “Viracta,” the “Company,” or the “combined company”, refer to Viracta Therapeutics, Inc. on a post-Merger basis, and the term “Private Viracta” refers to the business of privately-held Viracta Therapeutics, Inc., prior to the completion of the Merger. References to “Sunesis” refer to Sunesis Pharmaceuticals, Inc. prior to completion of the Merger. Pursuant to the terms of the Merger Agreement, each outstanding share of Private Viracta common stock outstanding immediately prior to the closing of the Merger was converted into approximately 0.1119 shares of Company common stock (the “Exchange Ratio”), after taking into account the Reverse Stock Split, as defined below. Immediately prior to the closing of the Merger, all shares of Private Viracta preferred stock then outstanding were exchanged into shares of common stock of Private Viracta. In addition, all outstanding options exercisable for common stock of Private Viracta and warrants exercisable for capital stock of Private Viracta became options and warrants exercisable for the same number of shares of common stock of the Company multiplied by the Exchange Ratio at an exercise price equal to the pre-Merger price divided by the Exchange Ratio. Immediately following the Merger, stockholders of Private Viracta owned approximately 86 % of the outstanding common stock of the combined company. This transaction was accounted for as a reverse asset acquisition in accordance with generally accepted accounting principles in the United States of America (“GAAP”), as Viracta was considered to be acquiring Sunesis and the Merger was accounted for as an asset acquisition, even though Sunesis was the legal acquirer and the issuer of the common stock in the Merger. This determination was primarily based on the facts that, immediately following the Merger: (i) Private Viracta’s stockholders owned a substantial majority of the voting rights in the combined company, (ii) Private Viracta designated a majority of the members of the initial board of directors of the combined company, and (iii) Private Viracta’s senior management holds all key positions in the senior management of the combined company. As a result, as of the closing date of the Merger, the net assets of Sunesis were recorded at their acquisition-date relative fair values in the accompanying condensed consolidated financial statements of the Company and the reported operating results prior to the Merger are those of Private Viracta. To determine the accounting for this transaction under GAAP, a company must assess whether an integrated set of assets and activities should be accounted for as an acquisition of a business or an asset acquisition. The guidance required an initial screen test to determine if substantially all of the fair value of the gross assets acquired was concentrated in a single asset or group of similar assets. The initial screen test was not met as there was no single asset or group of similar assets for Sunesis that represented a significant majority in this acquisition. However, at the time of the closing of the Merger, Sunesis did not have processes or an organized workforce that significantly contributed to its ability to create outputs, and substantially all of its fair value was concentrated in cash, working capital, and in-process research and development (“IPR&D”). As such, the acquisition was treated as an asset acquisition. Concurrent with the execution of the Merger Agreement, Private Viracta entered into an agreement for the sale of common stock in a private placement, which was completed immediately prior to the close of the Merger and resulted in gross proceeds of $ 65.0 million. In connection with the closing of the Merger and the concurrent private placement of common stock, the holders of the Company’s preferred stock waived their right to exchange their shares into any class of the Company’s stock other than common stock. On February 24, 2021, in connection with, and prior to the completion of, the Merger, the Company effected a 3.5-for-one reverse stock split of its then outstanding common stock (the “Reverse Stock Split”). The par value and the authorized shares of the common stock were not adjusted as a result of the Reverse Stock Split. Unless otherwise noted herein, references to share and per-share amounts give retroactive effect to the Reverse Stock Split and the Exchange Ratio which was effected upon the Merger. Liquidity and Risks As of March 31, 2022, the Company has devoted substantially all of its efforts to product development and has not realized product sales revenues from its planned principal operations. The Company has a limited operating history, and the sales and income potential of the Company’s business and market are unproven. The Company has experienced net losses since its inception and, as of March 31, 2022, had an accumulated deficit of $ 176.2 million. The Company expects to continue to incur net losses for at least the next several years. A successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. If the Company is unable to generate revenues adequate to support its cost structure, the Company will need to raise additional capital through the issuance of its common stock, through other equity or debt financings or through collaborations or partnerships with other companies. As of March 31, 2022, the Company had cash and cash equivalents of $ 92.2 million and working capital of $ 87.6 million. On November 4, 2021, the Company entered into a loan and security agreement with Silicon Valley Bank (“SVB”) and Oxford Finance LLC (“Oxford”), collectively referred to as “Lenders,” for up to $ 50.0 million, with $ 5.0 million refinanced at the time of entering into the agreement and $ 45.0 million available under certain circumstances. The second tranche of $ 20.0 million would be available upon request by the Company and Lenders approval until August 31, 2022, and the third tranche, $ 25.0 million, would be available at the Company's request subject to Lenders' discretion. As of March 31, 2022, neither tranche had been requested. Based on the Company’s current financial position and business plan, management believes that its existing cash and cash equivalents will be sufficient to fund the Company’s planned operations for at least twelve months from the issuance date of these condensed consolidated financial statements. The COVID-19 pandemic has caused significant business disruption around the globe. The effects of the COVID-19 pandemic continue to rapidly evolve, and the full impact of the COVID-19 pandemic remains highly uncertain and subject to change. The Company has taken certain measures and continues to evaluate other potential measures to mitigate the impact of the COVID-19 pandemic on our clinical trials. The Company does not yet know the full extent of potential delays or impacts on our business, our clinical trials, healthcare systems or the global economy as a whole. These effects could have a material impact on our operations, including the timing and ability of the Company to complete certain clinical trials and other efforts required to advance the development of its product candidates and raise additional capital.

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 and Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries and have been prepared in accordance with GAAP and follow the requirements of the U.S. Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. In management’s opinion, the unaudited interim financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position and its results of operations and its cash flows for the periods presented. These statements do not include all disclosures required by GAAP and should be read in conjunction with the Company’s financial statements and accompanying notes for the year ended December 31, 2021 , which are contained in the Company’s Current Report on Form 10-K filed with the SEC on March 17, 2022. The results for interim periods are not necessarily indicative of the results expected for the full fiscal year or any other interim period. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ materially from those estimates. Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash and cash equivalents. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents. Clinical Trial and Contracts Accruals The Company accrues clinical trial costs based on work performed. In determining the amount to accrue, the Company relies on estimates of total costs incurred based on enrollment, the completion of clinical trials and other events. The Company follows this method because it is believed to provide reasonably dependable estimates of the costs applicable to various stages of a clinical trial. However, the actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending on a number of factors. Differences between the actual clinical trial costs and the estimated clinical trial costs that have been accrued in any prior period are recognized in the subsequent period in which the actual costs become known. Historically, estimated accrued expenses have approximated actual expenses incurred; however, material differences could occur in the future. Research and Development Expenses Research and development costs are expensed as incurred. These costs consist primarily of salaries and other personnel-related expenses, including share-based compensation; facility-related expenses; and services performed by clinical research organizations, research institutions, and other outside service providers. The Company makes estimates of its accrued expenses as of each balance sheet date in the condensed consolidated financial statements based on facts and circumstances known to us at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. This process involves reviewing contract and purchase orders, reviewing the terms of vendor agreements, communicating with applicable personnel to identify services that have been performed on the Company's behalf and estimating the level of service performed and the associated cost incurred for the services when it has not yet been invoiced or otherwise notified of actual cost. The majority of the Company's service providers invoice monthly in arrears for services performed. Share-Based Compensation The Company accounts for share-based compensation expense related to stock options granted to employees, members of the board of directors, and outside consultants by estimating the fair value of each stock option on the date of grant using the Black-Scholes option pricing model. The Company accounts for restricted stock units (“RSUs”) by determining the fair value of each restricted stock unit based on the closing market price of the common stock on the date of grant. The Company recognizes share-based compensation on a straight-line basis over the requisite service period of the stock-based award, and forfeitures are recognized as they occur. The estimate of fair value for share-based compensation for stock options requires management to make estimates and judgments about, among other things, employee exercise behavior and volatility of the Company’s common stock. The judgments directly affect the amount of compensation expense that will be recognized. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is used in making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating in the United States. All long-lived assets were located in the United States at March 31, 2022 and December 31, 2021. Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market- based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets. Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The carrying amounts of the Company’s cash and cash equivalents, prepaid expenses, accounts payable and accrued liabilities approximate fair values for these financial instruments due to their short maturities. The money market funds, classified as cash equivalents, are Level 1 and had an amortized cost and estimated fair value of $ 14.9 million as of March 31, 2022 and December 31, 2021. The preferred stock warrant liability, a level 3 fair value measurement, was $ 0 as of March 31, 2022 and December 31, 2021, due to the reclassification to equity. The Company had no assets or liabilities measured at fair value on a recurring basis as of March 31, 2022 and December 31, 2021. Preferred Stock Warrant Liability The assumptions used in the Black-Scholes option pricing model to determine the fair value of the preferred stock warrant liability were as follows: February 24, 2021 Expected volatility 90.2 % Risk-free interest rate 1.38 % Expected dividend yield 0 % Expected term 9.3 years Fair value per share of preferred stock $ 17.15 The following table provides a reconciliation of the preferred stock warrant liability measured at fair value using Level 3 significant unobservable inputs (in thousands): Preferred Stock Balance at December 31, 2020 $ 106 Change in fair value of preferred stock warrant liability 290 Reclassification to equity ( 396 ) Balance at December 31, 2021 $ — Net Loss Per Share Basic loss per common share is computed by dividing net loss by the weighted average number of common shares and warrants to purchase common stock for nominal consideration outstanding during the period. Diluted loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding, plus the impact of common shares, if dilutive, resulting from the exercise of outstanding common stock equivalents. For all periods presented, there is no difference in the number of shares used to compute basic and diluted shares outstanding due to the Company's net loss position. The following securities are excluded from the calculation of weighted average dilutive common shares because their inclusion would have been anti-dilutive: March 31, 2022 2021 Shares issuable upon conversion of preferred stock 292,799 292,799 Common stock options and RSUs outstanding 6,277,172 4,266,928 Warrants to purchase common stock 23,100 23,100 Total excluded securities 6,593,071 4,582,827 Recent Adopted Accounting Pronouncements In October 2021, the FASB issued ASU No. 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers. The amendment requires acquiring entities to apply Topic 606 to recognize and measure contract assets and contract liabilities in a business combination. The ASU will be effective for the Company for the annual periods beginning after December 15, 2022, with early adoption permitted. The Company early adopted ASU 2021-08 in the fourth quarter of 2021 with no material impact on its condensed consolidated financial statements. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies that the Company will adopt as of the specified effective date. The Company has evaluated recently issued accounting pronouncements and as a result, based on the Company's preliminary assessment, do not believe any will have a material impact on the condensed consolidated financial statements or related footnote disclosures.

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2022
Disclosure Text Block [Abstract]
Collaboration and License Agreements	Collaboration and License Agreements Shenzhen Salubris Pharmaceuticals Co. Ltd. License Agreement On November 30, 2018, the Company entered into a License Agreement (the “Salubris Agreement”) with Shenzhen Salubris Pharmaceutical Co. Ltd., (“Salubris”), pursuant to which the Company granted an exclusive, royalty-bearing license, with the right to grant sublicenses to Salubris to research, develop, use, make, have made, sell, offer for sale, have sold, import, and otherwise commercialize nanatinostat in combination with an antiviral drug such as valganciclovir in the Republic of China, excluding Hong Kong, Macau, and Taiwan. On August 19, 2021, the Company, through its wholly-owned subsidiary, Viracta Subsidiary, Inc., entered into a Mutual Termination Agreement with Salubris, effective August 20, 2021 (the “Termination Agreement”), pursuant to which the parties agreed to terminate the Salubris Agreement. Under the terms of the Termination Agreement, the Company paid Salubris a payment in the amount of $ 4.0 million on the effective date of the Termination Agreement, and all licenses granted by the Company to Salubris automatically terminated. ImmunityBio License Agreement On May 1, 2017, the Company entered into a License Agreement (the “NK Agreement”) with ImmunityBio, Inc., formerly NantKwest, Inc. (“ImmunityBio”) whereby the Company granted an exclusive worldwide license to ImmunityBio and its affiliates to develop and commercialize nanatinostat for use in combination with NK cell immunotherapies. ImmunityBio will be responsible for conducting all necessary studies, including safety studies and clinical trials necessary in connection with seeking regulatory approvals to market the product in any territory. If ImmunityBio requires nanatinostat, the Company has the right to manufacture nanatinostat to be sold as part of a therapeutic product utilizing nanatinostat at a transfer price related to Viracta’s cost to ImmunityBio. In accordance with the NK Agreement, the Company is also eligible to receive up to a total of $ 100.0 million in milestone payments, with respect to the licensed products. The Company is eligible to earn tiered royalties on net sales of licensed products by ImmunityBio, its affiliates or sublicensees, ranging from the low to mid-single digits. The Company has recognized no revenue from milestones (variable consideration), which are fully constrained, or royalties to date. Unless earlier terminated, the NK Agreement will continue until the expiration of all applicable royalty terms on a product-by-product and country-by-country basis. There are no performance, cancellation, termination, or refund provisions in the arrangement that contain material financial consequences to the Company.

Financial Statement Details

Financial Statement Details	3 Months Ended
	Mar. 31, 2022
Financial Statement Details [Abstract]
Financial Statement Details	. Financial Statement Details Accrued expenses consist of the following (in thousands): March 31, December 31, 2022 2021 Accrued payroll and benefits $ 842 $ 1,695 Accrued clinical trial and contract expenses 2,711 3,380 Accrued professional services and expenses 217 180 Other accrued expenses 382 547 Total accrued expenses $ 4,152 $ 5,802

XOMA Transaction

XOMA Transaction	3 Months Ended
	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
XOMA Transaction	. XOMA Transaction In December 2019, the Company entered into a license agreement with DOT Therapeutics-1, LLC (“DOT-1”) to grant DOT-1 a worldwide, exclusive license of DAY101. The DOT-1 license agreement includes up to $ 57 .0 million in potential pre-commercialization, event-based milestone payments and royalty payments on future sales of DAY101, when and if approved and commercialized, $ 3.0 million of which was received by the Company prior to the XOMA Transaction. Also in December 2019, the Company entered into an agreement to license vosaroxin to Denovo Biopharma LLC, which includes up to $ 57.0 million in potential regulatory and commercial milestones, and double-digit royalties on future sales of vosaroxin, when and if approved and commercialized. The potential milestone and royalty payments related to DAY101 and vosaroxin were sold in the XOMA Transaction. On March 22, 2021, the Company entered into a Royalty Purchase Agreement with XOMA (US) LLC (“XOMA”), in which XOMA purchased the potential future milestones and royalties associated with existing licenses relating to two clinical-stage product candidates, DAY101 and vosaroxin, which were obtained in the Merger (the “XOMA Transaction”). The Company received an upfront payment of $ 13.5 million and may receive up to $ 20.0 million in a pre-commercialization, event-based milestone. The upfront payment is nonrefundable, there are no clawback provisions, and the Company has no significant involvement or obligations going forward related to potential future milestones and royalties. The Company has recognized no income from the pre-commercialization, event-based milestone to date.

Debt

Debt	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Debt	6. Debt Loan Agreement On July 30, 2020, Private Viracta and Silicon Valley Bank (the “Lender”) entered into a loan and security agreement (the “SVB Loan Agreement”), providing for up to $ 15.0 million in four tranches. Upon entering into the SVB Loan Agreement, Private Viracta borrowed $ 5.0 million. The loan was due on the scheduled maturity date of July 1, 2024 and had an interest only period through January 31, 2022, followed by 30 equal monthly payments of principal plus accrued interest commencing on February 1, 2022. The per annum interest rate for any outstanding loan was the lesser of (i) 10 %, or (ii) the greater of (A) 3.5 % above the prime rate or (B) 6.75 %. The interest rate as of December 31, 2020 was 6.75 % per annum. In addition, a final payment of 7.0 % of the amount of the loan drawn was due on the earlier of the Maturity Date, acceleration of the loan, or prepayment of the loan. The final payment was accrued through interest expense using the effective interest method. The debt issuance costs and warrants issued (Note 8) were accounted for as a debt discount. The debt discount was being amortized as interest expense over the term of the loan using the effective interest method. If the Company elected to prepay the loan, a prepayment fee equal to 1 % or 2 % of the then outstanding principal balance was also due, depending upon when the prepayment occurs. No prepayment fee is charged if the credit is replaced with a new facility from the same bank. On November 4, 2021, the Company entered into a new loan and security agreement (the “Loan Agreement”) with SVB and Oxford for up to $ 50.0 million. In connection with entering the new $ 50.0 million credit facility, the Company and SVB agreed to terminate the Company’s prior $ 15.0 million loan and security agreement with SVB. The existing $ 5.0 million debt balance from the Company’s previous credit facility with SVB was relieved under this new $ 50.0 million credit facility. The Loan Agreement was accounted for as a modification based on the effect of changes in terms from the original SVB Loan Agreement. Under the terms of the $ 50.0 million credit facility, the remaining $ 45.0 million is available in two additional tranches of $ 20.0 million and $ 25.0 million under certain circumstances, and the Company is under no obligation to draw funds in the future. The second tranche of $20.0 million would be available upon request by the Company and Lenders approval until August 31, 2022, and the third tranche, $25.0 million, would be available at the Company's request subject Lenders' discretion. As of March 31, 2022, neither tranche had been requested. The loan will be due on the scheduled maturity date of November 1, 2026 (the “Maturity Date”). In accordance with the original terms of the Loan Agreement, repayment of the loan is interest only through December 31, 2023, and if evidence of positive Phase 1(b) data in the EBV + solid tumor trial sufficient to advance into Phase 2 is delivered to the Lenders and confirmed by the Company's board of directors prior to December 31, 2023 (the “Milestone”), the interest-only period would be extended through December 31, 2024. This period of interest only will be followed by 35 equal monthly payments of principal plus accrued interest commencing on January 1, 2024, or if the Milestone is achieved, the period of interest only will be followed by 23 equal monthly payments of principal plus accrued interest commencing on January 1, 2025. The per annum interest rate for any outstanding loan is equal to the greater of (i) 8.15 % and (ii) the sum of (a) the Prime Rate, as reported in The Wall Street Journal on the last business day of the month that immediately precedes the month in which the interest will accrue, plus (b) 4.90 %. In addition, a final payment of 5.0 % of the amount of the loan drawn will be due on the earlier of the Maturity Date, acceleration of the loan, or prepayment of the loan. The final payment is being accrued through interest expense using the effective interest method. If the Company elects to prepay the loan, a prepayment fee equal to 1 % or 2 % of the then outstanding principal balance will also be due, depending upon when the prepayment occurs. If the Company elects to not draw certain portions of the loan, the Company will incur a 3 % fee of the undrawn portion. The Company is subject to customary affirmative and restrictive covenants under the Loan Agreement. The Company’s obligations under the Loan Agreement are secured by a first priority security interest in substantially all of its current and future assets, other than the Company's intellectual property. The Company has also agreed not to encumber its intellectual property assets, except as permitted by the Loan Agreement. As of March 31, 2022, the Company was in compliance with nonfinancial covenants. The Loan Agreement also contains customary indemnification obligations and customary events of default, including, among other things, the Company’s failure to fulfill certain obligations under the Loan Agreement and the occurrence of a material adverse change in the Company’s business, operations, or condition (financial or otherwise), a material impairment of the prospect of repayment of any portion of the loan, or a material impairment in the perfection or priority of Lenders' lien in the collateral or in the value of such collateral. In the event of default by the Company under the Loan Agreement, the Lenders would be entitled to exercise their remedies thereunder, including the right to accelerate the debt, upon which the Company may be required to repay all amounts then outstanding under the Loan Agreement. As of March 31, 2022, the Company was in compliance with all financial covenants under the Loan Agreement and there had been no material adverse change. The debt issuance costs are being accounted for as a debt discount. The debt discount is being amortized as interest expense over the term of the loan using the effective interest method. The carrying value of the debt approximates the fair value (Level 2) as of March 31, 2022. The following table summarizes future principal payments (in thousands) under the terms of the Loan Agreement: Years Ending December 31, 2022 (remaining) $ — 2023 — 2024 1,714 2025 1,714 Thereafter 1,572 Total future principal payments 5,000 Unamortized discount ( 159 ) Total, net $ 4,841

Merger

Merger	3 Months Ended
	Mar. 31, 2022
Business Combinations [Abstract]
Merger	7. Merger The Merger, which closed on February 24, 2021, was accounted for as a reverse asset acquisition pursuant to Topic 805, Business Combinations , as substantially all of its fair value was concentrated in cash, working capital, and IPR&D. As the IPR&D assets had no alternative future use, the fair value attributable to these assets was recorded as acquired IPR&D in the Company’s condensed consolidated statements of operations for the three months ended March 31, 2021. The estimated fair value of total consideration given was $ 103.4 million based on 5,173,772 shares of Sunesis common stock and 10,248 shares of Sunesis convertible preferred stock (or 292,799 Sunesis common shares on an as-converted basis) outstanding immediately prior to the merger date. The number of outstanding common stock and preferred stock on an as-converted basis was multiplied by the Sunesis closing common stock price of $ 18.62 on the date of the merger, plus transaction costs of $ 1.6 million, to determine the estimated fair value of total consideration. The allocation of the purchase price is as follows (in thousands): Net assets acquired (1) $ 18,956 Acquired IPR&D (2) 84,478 Purchase price $ 103,434 (1) Net assets acquired (in thousands): Cash and cash equivalents $ 17,143 Prepaid expenses and other assets 3,768 Accounts payable and accrued liabilities ( 1,955 ) Net assets acquired $ 18,956 (2) Represents the research and development projects of Sunesis which were in-process, but not yet completed. Current accounting standards require that the fair value of IPR&D projects acquired in an asset acquisition with no alternative future use be allocated a portion of the consideration transferred and charged to expense on the acquisition date. The acquired IPR&D assets did not have outputs or employees.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2022
Stockholders' Equity Note [Abstract]
Stockholders' Equity	8. Stockholders’ Equity Common Stock The total number of shares of common stock of Viracta outstanding as of March 31, 2022 and December 31, 2021 was 37,486,177 and 37,424,863 , respectively. Concurrent Financing On February 24 2021, immediately prior to the closing of the Merger, the Company completed the February 2021 private placement offering of an aggregate of 12,012,369 shares of common stock for gross proceeds of $ 65.0 million and incurred fees and other offering costs of $ 2.7 million. Sale Agreement On May 28, 2021, the Company entered into an Open Market Sale Agreement SM (the “Sale Agreement”) with Jefferies LLC (the “Sales Agent”), under which the Company may offer and sell up to $ 50.0 million shares (the “Shares”) of its common stock, par value $ 0.0001 per share (“Common Stock”), from time to time through the Sales Agent. The sales and issuances, if any, of the Shares by the Company under the Sale Agreement will be pursuant to the Company’s registration statement on Form S-3 (the “Registration Statement”), filed with the SEC on May 28, 2021 and declared effective by the SEC on June 4, 2021. Sales, if any, of the Shares pursuant to the Sale Agreement may be made in negotiated transactions or transactions that are deemed to be “at the market offerings” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended, including sales made directly on The Nasdaq Stock Market, or sales made into any other existing trading market for the Common Stock. The Sales Agent is not required to sell any specific amount of securities, but will act as the Company’s sales agent using commercially reasonable efforts to sell the Shares from time to time, consistent with its normal trading and sales practices, applicable state and federal laws, rules and regulations and the rules of The Nasdaq Stock Market, based upon instructions from the Company (including any price, time or size limits or other customary parameters or conditions the Company may impose). As of March 31, 2022, the Company has incurred legal and accounting costs of $ 0.1 million related to the Sale Agreement. As of March 31, 2022, no shares had been issued pursuant to the Sale Agreement. Convertible Preferred Stock In connection with the Merger, all of the outstanding shares of Private Viracta’s convertible preferred stock were converted into 18,811,552 shares of the Company’s common stock. With the Merger, the Company obtained 10,000,000 shares of authorized preferred stock available for future issuance in one or more series. Upon issuance, the Company can determine the rights, preferences, privileges and restrictions thereof. These rights, preference and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. There were 10,248 shares of this preferred stock outstanding as of March 31, 2022 , of which 1,915 shares were Series E Stock and 8,333 shares were Series F Stock. The Series E Stock and Series F Stock are non-voting Series E and Series F Convertible Preferred Stock at a stated price of $ 500 and $ 600 per share, respectively. Each share of non-voting Series E Stock and Series F Stock is convertible at a conversion ratio equal to the stated price divided by the conversion price, which is $ 17.50 per share and $ 21.00 per share, respectively, provided that conversion will be prohibited if, as a result, the holder and its affiliates would own more than 9.98 % of the total number of shares of common stock then outstanding. In the event of the Company’s liquidation, dissolution, or winding up, holders of Series E and Series F Stock will receive a payment equal to $ 0.0001 per share of Series E and Series F Stock before any proceeds are distributed to the holders of Common Stock. Shares of Series E and Series F Stock will generally have no voting rights, except as required by law and except that the consent of holders of a majority of this outstanding Series E Stock will be required to amend the terms of the Series E and Series F Stock. Shares of the Series E and Series F Stock will not be entitled to receive any dividends, unless and until specifically declared by the Company’s board of directors, and will rank: • senior to all of the Company’s Common Stock; • senior to any class or series of the Company’s capital stock hereafter created specifically ranking by its terms junior to the Series E and Series F Stock; • on parity with any class or series of the Company’s capital stock hereafter created specifically ranking by its terms on parity with the Series E and Series F Stock; and • junior to any class or series of the Company’s capital stock hereafter created specifically ranking by its terms senior to the Series E and Series F Stock; in each case, as to distributions of assets upon the Company’s liquidation, dissolution or winding up whether voluntarily or involuntarily. Warrants Concurrent with the issuance of convertible promissory notes in 2018, the Company issued to the note investors warrants to purchase 250,323 shares of Viracta Common Stock (the “Common Warrants”). The Common Warrants’ exercise price is $ 0.09 per share. Unless previously exercised, the Common Warrants will expire on the seven-year anniversary of the date of issuance. As of March 31, 2022 , Common Warrants to purchase 86,209 shares of Viracta Common Stock remain unexercised. These shares have been included in the weighted average shares outstanding for both basic and diluted earnings per share for the three months ended March 31, 2022 and 2021 as their exercise price is for nominal consideration. In July 2020, the Company issued warrants exercisable for 206,440 pre-merger shares of Series E preferred stock, at a pre-merger exercise price of $ 0.6055 per share, to Silicon Valley Bank in conjunction with the Company’s entry into the SVB Loan Agreement (the “Lender Warrants”). Upon completion of the Merger, the Lender Warrants became exercisable for 23,100 shares of common stock at an exercise price of $ 5.42 per share. The Lender Warrants will expire, if not previously exercised, on July 30, 2030. Common Stock Reserved for Future Issuance Common stock reserved for future issuance are as follows in common equivalent shares: March 31, December 31, 2022 2021 Conversion of preferred stock 292,799 292,799 Common stock warrants 109,309 109,309 Stock options issued and outstanding for all plans 5,584,764 4,051,572 RSUs outstanding 692,408 745,668 Authorized for future option grants 1,500,358 1,169,523 Common stock authorized for the ESPP 60,948 60,948 Total 8,240,586 6,429,819 Equity Incentive Plans In January 2017, the Company adopted the Viracta Therapeutics, Inc. 2016 Equity Incentive Plan (the “2016 Plan”), which permitted stock option and restricted stock unit grants to employees, members of the board of directors, and outside consultants. The Plan allowed for grants of incentive stock options with exercise prices of at least 100 % of the fair market value of Viracta’s common stock, nonqualified options with exercise prices of at least 85 % of the fair market value of the Company’s common stock, restricted stock, and restricted stock units. All stock options granted under the 2016 Plan have a ten-year life and generally vest over zero to four years . In connection with the closing of the Merger, no further awards will be made under the 2016 Plan but the 2016 Plan will continue to govern the terms and conditions of the outstanding awards previously granted under the 2016 Plan. At the time of the close of the Merger, the Company adopted the Viracta Therapeutics, Inc. 2021 Equity Incentive Plan (the “2021 Plan”), which also permits stock options and restricted stock unit grants to employees, members of the board of directors, and outside consultants. The maximum number of shares of the Company’s common stock available for issuance under the 2021 Plan equals the sum of (a) 2,628,571 shares; (b) any shares of common stock of the Company which are subject to awards under the Sunesis 2011 Equity Incentive Plan (the “Sunesis 2011 Plan”) or the 2016 Plan as of the effective date of the 2021 Plan which become available for issuance under the 2021 Plan after such date in accordance with its terms; and (c) an annual increase on the first day of each calendar year beginning with January 1 of the calendar year following the effectiveness of the 2021 Plan and ending with the last January 1 during the initial ten year term of the 2021 Plan. This annual increase would be equal to the lesser of (i) 3,771,428 shares, (ii) five percent of the number of shares of the Company’s common stock outstanding (on an as-converted basis) on the final day of the immediately preceding calendar year, and (iii) such number of shares of the Company’s common stock as determined by the Company’s board of directors. The 2021 Plan allows for grants of incentive stock options with exercise prices of at least 100 % of the fair market value of Viracta’s common stock, nonqualified options with exercise prices of at least 100 % of the fair market value of the Company’s common stock, restricted stock, and restricted stock units. All stock options granted to date have a ten-year life and generally vest over zero to four years . As of March 31, 2022, there we re 985,358 shares available for issuance under the 2021 Plan. Additionally, in connection with the closing of the Merger, no further awards will be made under the Sunesis 2011 Plan. As of March 31, 2022, 84,591 fully vested options remain outstanding under the Sunesis 2011 Plan with a weighted average exercise price of $ 28.18 per share. The compensation cost that has been included in the accompanying condensed consolidated statements of operations for all share-based compensation arrangements is detailed as follows (in thousands): Three Months Ended March 31, 2022 2021 Research and development $ 646 $ 307 General and administrative 1,126 337 Total $ 1,772 $ 644 On June 30, 2021, the Company adopted the 2021 Inducement Equity Incentive Plan (the “2021 Inducement Plan”) and reserved 1,000,000 shares for future grant under the 2021 Inducement Pla n. As of March 31, 2022, there we re 515,000 shares available for issuance under the 2021 Inducement Plan. Stock Options The Company recorded share-based compensation related to stock options of $ 1.6 million and $ 0.5 million fo r the three months ended March 31, 2022 and 2021, respectively. Fair value is determined on the date of grant for options. Compensation expense is recognized over the vesting period based on the fair value of the options. The fair value of stock options is estimated using the Black-Scholes model with the assumptions disclosed in the following table: Three Months Ended March 31, 2022 2021 Risk free interest rate 1.82 % - 2.19 % 0.66 % - 1.09 % Expected option term 6.3 years 5.8 - 6.3 years Expected volatility of common stock 84.02 % - 84.66 % 90.2 % Expected dividend yield 0.0 % 0.0 % The expected term of stock options is based on the simplified method, which is an average of the contractual term of the option and its vesting period. The expected volatility of stock options is based upon the historical volatility of a number of publicly traded companies in similar stages of clinical development. The risk-free interest rate is based on the average yield of U.S. Treasury Bills appropriate for the expected term of the stock option grants. The Company has not historically paid cash dividends and does not anticipate declaring dividends in the future. As of March 31, 2022, unrecognized compensation expense related to unvested options granted totaled $ 19.2 million. The expense is expected to be recognized over a weighted-average period of 3.0 years. A summary of the stock option activity under the 2016 Plan and the 2021 Plan during the period ended March 31, 2022 is presented below (in thousands except for per share and weighted average term): Number of Weighted Weighted Outstanding at December 31, 2021 3,964 $ 7.33 8.9 Granted 1,605 $ 3.03 Exercised ( 7 ) $ 0.96 Cancelled ( 62 ) $ 3.27 Outstanding at March 31, 2022 5,500 $ 6.13 9.1 Outstanding at March 31, 2022 (Sunesis 2011 Plan) 85 $ 28.18 3.1 Restricted Stock Units The Company recorded share-based compensation related to RSUs of $ 0.2 million and $ 0.1 million for the three months ended March 31, 2022 and 2021, respectively. For RSU equity awards, grant date fair value is estimated using the closing stock price on the date of grant. Compensation expense is recognized over the vesting period based on the fair value of the RSUs. A summary of the restricted stock unit activity under the plans during the period ended March 31, 2022 is presented below (in thousands except for per share and weighted average term): RSUs Weighted Weighted Outstanding at December 31, 2021 745 $ 4.22 — Granted — — Vested ( 53 ) 4.22 Cancelled — — Outstanding at March 31, 2022 692 $ 4.22 3.2 As of March 31, 2022, unrecognized compensation expense related to unvested RSUs total ed $ 2.5 million. The expense is expected to be recognized over a weighted-average period of 3.2 years. Employee Stock Purchase Plan The Company adopted the 2011 Employee Stock Purchase Plan (the “2011 ESPP”) as part of the Merger. The 2011 ESPP permits eligible employees to purchase common stock at a discount through payroll deductions during defined offering periods. Eligible employees can purchase shares of the Company’s common stock at 85 % of the lower of the fair market value of the common stock at (i) the beginning of a 12-month offering period, or (ii) at the end of one of the two related 6-month purchase periods. No participant in the 2011 ESPP may be issued or transferred shares of common stock valued at more than $ 25,000 per calendar year. As of March 31, 2022, there were 60,948 shares availab le for future issuance under the ESPP.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Leases In June 2020, the Company amended the existing office leases to enter into a noncancelable operating lease to extend the lease terms through August 2023 with a renewal option for an additional year (“Amended Lease”). The Amended Lease monthly base rent will increase approximately 4 % annually from $ 20,019 to $ 21,444 over the life of the lease, including utilities and other operating costs. Upon the execution of the Amended Lease, the Company recorded an operating lease right-of-use (“ROU”) asset and corresponding lease liability for $ 667,000 . In August 2020, the Company entered into an additional noncancelable operating lease agreement for certain office space with a lease term from August 2020 through August 2023 with a renewal option for an additional year (“New Lease”). The New Lease also includes a buyout option to terminate the lease prior to its expiration with at least one month’s prior written notice and a one-time payment equal to four months’ rent. The New Lease monthly base rent will increase approximately 4 % to 9 % from $ 12,462 to $ 14,033 over the life of the lease, including utilities and other operating costs. In connection with the execution of the New Lease, the Company recorded an operating lease ROU asset and corresponding lease liability for $ 439,000 . Total lease expense for the three months ended March 31, 2022 and 2021 was $ 104,000 and $ 71,000 , respectively. At March 31, 2022, the Company had remaining lease liabilities of $ 567,000 of which $ 175,000 was recorded as noncurrent lease liability as of March 31, 2022, and operating lease ROU assets of $ 549,000 . Total cash paid for amounts included in the measurement of operating lease liabilities was $ 105,000 and $ 99,000 for the three months ended March 31, 2022 and 2021 , respectively. The weighted average discount rate for the operating leases recorded in 2020 was 8.0 % and the weighted average remaining lease term was 1.4 years as of March 31, 2022. Indemnifications As permitted under Delaware law, the Company indemnifies its officers, directors, and employees for certain events and occurrences while the officer, or director is, or was, serving at the Company’s request in such capacity.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries and have been prepared in accordance with GAAP and follow the requirements of the U.S. Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. In management’s opinion, the unaudited interim financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position and its results of operations and its cash flows for the periods presented. These statements do not include all disclosures required by GAAP and should be read in conjunction with the Company’s financial statements and accompanying notes for the year ended December 31, 2021 , which are contained in the Company’s Current Report on Form 10-K filed with the SEC on March 17, 2022. The results for interim periods are not necessarily indicative of the results expected for the full fiscal year or any other interim period.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of expenses during the reporting period. Actual results could differ materially from those estimates.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash and cash equivalents.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents.
Clinical Trial and Contracts Accruals	Clinical Trial and Contracts Accruals The Company accrues clinical trial costs based on work performed. In determining the amount to accrue, the Company relies on estimates of total costs incurred based on enrollment, the completion of clinical trials and other events. The Company follows this method because it is believed to provide reasonably dependable estimates of the costs applicable to various stages of a clinical trial. However, the actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending on a number of factors. Differences between the actual clinical trial costs and the estimated clinical trial costs that have been accrued in any prior period are recognized in the subsequent period in which the actual costs become known. Historically, estimated accrued expenses have approximated actual expenses incurred; however, material differences could occur in the future.
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. These costs consist primarily of salaries and other personnel-related expenses, including share-based compensation; facility-related expenses; and services performed by clinical research organizations, research institutions, and other outside service providers. The Company makes estimates of its accrued expenses as of each balance sheet date in the condensed consolidated financial statements based on facts and circumstances known to us at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. This process involves reviewing contract and purchase orders, reviewing the terms of vendor agreements, communicating with applicable personnel to identify services that have been performed on the Company's behalf and estimating the level of service performed and the associated cost incurred for the services when it has not yet been invoiced or otherwise notified of actual cost. The majority of the Company's service providers invoice monthly in arrears for services performed.
Share-Based Compensation	Share-Based Compensation The Company accounts for share-based compensation expense related to stock options granted to employees, members of the board of directors, and outside consultants by estimating the fair value of each stock option on the date of grant using the Black-Scholes option pricing model. The Company accounts for restricted stock units (“RSUs”) by determining the fair value of each restricted stock unit based on the closing market price of the common stock on the date of grant. The Company recognizes share-based compensation on a straight-line basis over the requisite service period of the stock-based award, and forfeitures are recognized as they occur. The estimate of fair value for share-based compensation for stock options requires management to make estimates and judgments about, among other things, employee exercise behavior and volatility of the Company’s common stock. The judgments directly affect the amount of compensation expense that will be recognized.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is used in making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating in the United States. All long-lived assets were located in the United States at March 31, 2022 and December 31, 2021.
Fair Value Measurements	Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market- based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets. Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The carrying amounts of the Company’s cash and cash equivalents, prepaid expenses, accounts payable and accrued liabilities approximate fair values for these financial instruments due to their short maturities. The money market funds, classified as cash equivalents, are Level 1 and had an amortized cost and estimated fair value of $ 14.9 million as of March 31, 2022 and December 31, 2021. The preferred stock warrant liability, a level 3 fair value measurement, was $ 0 as of March 31, 2022 and December 31, 2021, due to the reclassification to equity. The Company had no assets or liabilities measured at fair value on a recurring basis as of March 31, 2022 and December 31, 2021.
Preferred Stock Warrant Liability	Preferred Stock Warrant Liability The assumptions used in the Black-Scholes option pricing model to determine the fair value of the preferred stock warrant liability were as follows: February 24, 2021 Expected volatility 90.2 % Risk-free interest rate 1.38 % Expected dividend yield 0 % Expected term 9.3 years Fair value per share of preferred stock $ 17.15 The following table provides a reconciliation of the preferred stock warrant liability measured at fair value using Level 3 significant unobservable inputs (in thousands): Preferred Stock Balance at December 31, 2020 $ 106 Change in fair value of preferred stock warrant liability 290 Reclassification to equity ( 396 ) Balance at December 31, 2021 $ —
Net Loss Per Share	Net Loss Per Share Basic loss per common share is computed by dividing net loss by the weighted average number of common shares and warrants to purchase common stock for nominal consideration outstanding during the period. Diluted loss per common share is computed by dividing net loss by the weighted average number of common shares outstanding, plus the impact of common shares, if dilutive, resulting from the exercise of outstanding common stock equivalents. For all periods presented, there is no difference in the number of shares used to compute basic and diluted shares outstanding due to the Company's net loss position. The following securities are excluded from the calculation of weighted average dilutive common shares because their inclusion would have been anti-dilutive: March 31, 2022 2021 Shares issuable upon conversion of preferred stock 292,799 292,799 Common stock options and RSUs outstanding 6,277,172 4,266,928 Warrants to purchase common stock 23,100 23,100 Total excluded securities 6,593,071 4,582,827
Recent Accounting Pronouncements	Recent Adopted Accounting Pronouncements In October 2021, the FASB issued ASU No. 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers. The amendment requires acquiring entities to apply Topic 606 to recognize and measure contract assets and contract liabilities in a business combination. The ASU will be effective for the Company for the annual periods beginning after December 15, 2022, with early adoption permitted. The Company early adopted ASU 2021-08 in the fourth quarter of 2021 with no material impact on its condensed consolidated financial statements. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies that the Company will adopt as of the specified effective date. The Company has evaluated recently issued accounting pronouncements and as a result, based on the Company's preliminary assessment, do not believe any will have a material impact on the condensed consolidated financial statements or related footnote disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Fair Value Measurement Inputs and Valuation Techniques	The assumptions used in the Black-Scholes option pricing model to determine the fair value of the preferred stock warrant liability were as follows: February 24, 2021 Expected volatility 90.2 % Risk-free interest rate 1.38 % Expected dividend yield 0 % Expected term 9.3 years Fair value per share of preferred stock $ 17.15
Summary of reconciliation of warrant liability measured at fair value	The following table provides a reconciliation of the preferred stock warrant liability measured at fair value using Level 3 significant unobservable inputs (in thousands): Preferred Stock Balance at December 31, 2020 $ 106 Change in fair value of preferred stock warrant liability 290 Reclassification to equity ( 396 ) Balance at December 31, 2021 $ —
Summary of antidilutive securities excluded from the calculation of weighted average dilutive common shares	The following securities are excluded from the calculation of weighted average dilutive common shares because their inclusion would have been anti-dilutive: March 31, 2022 2021 Shares issuable upon conversion of preferred stock 292,799 292,799 Common stock options and RSUs outstanding 6,277,172 4,266,928 Warrants to purchase common stock 23,100 23,100 Total excluded securities 6,593,071 4,582,827

Financial Statement Details (Ta

Financial Statement Details (Tables)	3 Months Ended
	Mar. 31, 2022
Financial Statement Details [Abstract]
Schedule of Accrued Liabilities	Accrued expenses consist of the following (in thousands): March 31, December 31, 2022 2021 Accrued payroll and benefits $ 842 $ 1,695 Accrued clinical trial and contract expenses 2,711 3,380 Accrued professional services and expenses 217 180 Other accrued expenses 382 547 Total accrued expenses $ 4,152 $ 5,802

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Summary of Future Minimum Payments Under Loan Facility	The following table summarizes future principal payments (in thousands) under the terms of the Loan Agreement: Years Ending December 31, 2022 (remaining) $ — 2023 — 2024 1,714 2025 1,714 Thereafter 1,572 Total future principal payments 5,000 Unamortized discount ( 159 ) Total, net $ 4,841

Merger (Tables)

Merger (Tables)	3 Months Ended
	Mar. 31, 2022
Business Combinations [Abstract]
Summary of Allocation of the Purchase Price To Assets and Liabilities Acquired	The allocation of the purchase price is as follows (in thousands): Net assets acquired (1) $ 18,956 Acquired IPR&D (2) 84,478 Purchase price $ 103,434 (1) Net assets acquired (in thousands): Cash and cash equivalents $ 17,143 Prepaid expenses and other assets 3,768 Accounts payable and accrued liabilities ( 1,955 ) Net assets acquired $ 18,956 (2) Represents the research and development projects of Sunesis which were in-process, but not yet completed. Current accounting standards require that the fair value of IPR&D projects acquired in an asset acquisition with no alternative future use be allocated a portion of the consideration transferred and charged to expense on the acquisition date. The acquired IPR&D assets did not have outputs or employees.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2022
Stockholders' Equity Note [Abstract]
Shares of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance are as follows in common equivalent shares: March 31, December 31, 2022 2021 Conversion of preferred stock 292,799 292,799 Common stock warrants 109,309 109,309 Stock options issued and outstanding for all plans 5,584,764 4,051,572 RSUs outstanding 692,408 745,668 Authorized for future option grants 1,500,358 1,169,523 Common stock authorized for the ESPP 60,948 60,948 Total 8,240,586 6,429,819
Summary of Shared Based Compensation Cost Included in Condensed Statement Of Operations	The compensation cost that has been included in the accompanying condensed consolidated statements of operations for all share-based compensation arrangements is detailed as follows (in thousands): Three Months Ended March 31, 2022 2021 Research and development $ 646 $ 307 General and administrative 1,126 337 Total $ 1,772 $ 644
Summary of fair value of stock options is estimated using the Black-Scholes model	The fair value of stock options is estimated using the Black-Scholes model with the assumptions disclosed in the following table: Three Months Ended March 31, 2022 2021 Risk free interest rate 1.82 % - 2.19 % 0.66 % - 1.09 % Expected option term 6.3 years 5.8 - 6.3 years Expected volatility of common stock 84.02 % - 84.66 % 90.2 % Expected dividend yield 0.0 % 0.0 %
Summary of Stock Option Activity for Company's Stock Option Plans	A summary of the stock option activity under the 2016 Plan and the 2021 Plan during the period ended March 31, 2022 is presented below (in thousands except for per share and weighted average term): Number of Weighted Weighted Outstanding at December 31, 2021 3,964 $ 7.33 8.9 Granted 1,605 $ 3.03 Exercised ( 7 ) $ 0.96 Cancelled ( 62 ) $ 3.27 Outstanding at March 31, 2022 5,500 $ 6.13 9.1 Outstanding at March 31, 2022 (Sunesis 2011 Plan) 85 $ 28.18 3.1
Summary of Restricted Stock Units Activity	A summary of the restricted stock unit activity under the plans during the period ended March 31, 2022 is presented below (in thousands except for per share and weighted average term): RSUs Weighted Weighted Outstanding at December 31, 2021 745 $ 4.22 — Granted — — Vested ( 53 ) 4.22 Cancelled — — Outstanding at March 31, 2022 692 $ 4.22 3.2

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Detail) $ in Thousands	Feb. 24, 2021	Feb. 28, 2021USD ($)	Mar. 31, 2022USD ($)	Dec. 31, 2021USD ($)	Nov. 04, 2021USD ($)
Accumulated deficit			$ (176,223)	$ (165,677)
Cash and cash equivalents			92,199	$ 103,554
Working capital			$ 87,600
Gross proceeds from private placement		$ 65,000
Reverse stock split	3.5-for-one
Percentage of outstanding common stock of combined company			86.00%
Conversion ratio			0.1119
Line of credit maximum borrowing amount					$ 50,000
Line of Credit Facility, Remaining Borrowing Capacity					45,000
Silicon Valley Bank ("SVB") and Oxford Finance LLC ("Oxford") [Member]
Line of credit maximum borrowing amount					50,000
Line of Credit Facility, Current Borrowing Capacity					5,000
Line of Credit Facility, Remaining Borrowing Capacity					45,000
Tranche Two [Member]
Line of Credit Facility, Remaining Borrowing Capacity					25,000
Tranche Two [Member] | Silicon Valley Bank ("SVB") and Oxford Finance LLC ("Oxford") [Member]
Line of Credit Facility, Remaining Borrowing Capacity					20,000
Tranche Three [Member] | Silicon Valley Bank ("SVB") and Oxford Finance LLC ("Oxford") [Member]
Line of Credit Facility, Remaining Borrowing Capacity					$ 25,000
Royalty Purchase Agreement [member]
Upfront payment received			$ 13,500

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Summary of Fair Value Measurement Inputs and Valuation Techniques (Detail) - Preferred Stock Warrant Liability [Member]	Feb. 24, 2021UsDollarsShareyr
Measurement Input, Price Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and Rights Outstanding, Measurement Input	90.2
Measurement Input, Risk Free Interest Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and Rights Outstanding, Measurement Input	1.38
Measurement Input, Expected Dividend Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and Rights Outstanding, Measurement Input	0
Measurement Input, Expected Term [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and Rights Outstanding, Measurement Input | yr	9.3
Measurement Input, Share Price [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrants and Rights Outstanding, Measurement Input | UsDollarsShare	17.15

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Reconciliation of Warrant Liability Measured at Fair Value (Detail) - Preferred Stock Warrant Liability [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Opening , Balance	$ 106
Change in fair value of preferred stock warrant liability	290
Reclassification to equity	(396)
Ending , Balance	$ 0

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on recurring basis	$ 0	$ 0
Fair Value, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred stock warrant liability noncurrent	0
Fair Value Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money Market Funds Fair Value	14,900
Royalty Purchase Agreement [member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Upfront payment received	13,500
Milestone payment received in the future	$ 20,000

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Antidilutive Securities Excluded From the Calculation of Weighted Average Dilutive Common Shares (Detail) - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	6,593,071	4,582,827
Shares issuable upon conversion of preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	292,799	292,799
Common stock options and RSUs outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	6,277,172	4,266,928
Warrants to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	23,100	23,100

Collaboration and License Agr_2

Collaboration and License Agreements (Additional Information) (Details) - USD ($) $ in Millions	Aug. 19, 2021	May 01, 2017
Termination Agreement [Member]
Related Party Transaction [Line Items]
Amount paid on the termination of agreement	$ 4
NK Agreement [Member]
Related Party Transaction [Line Items]
Milestone payments to be received		$ 100

Financial Statement Details -

Financial Statement Details - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued payroll and benefits	$ 842	$ 1,695
Accrued clinical trial and contract expenses	2,711	3,380
Accrued professional services and expenses	217	180
Other accrued expenses	382	547
Total accrued expenses	$ 4,152	$ 5,802

XOMA Transaction - Additional i

XOMA Transaction - Additional information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
Royalty Purchase Agreement [member]
Upfront payment received	$ 13.5
Milestone payment received in the future	$ 20
DOT-1 License Agreement [Member] | License Agreement Terms [Member]
Potential pre-commercialization payments receivable		$ 57
Development milestone payment received		$ 3
Regulatory, commercial milestones payments and double-digit royalty payments, receivable			$ 57

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($) $ in Millions	Nov. 04, 2021	Mar. 31, 2022	Dec. 31, 2020	Jul. 30, 2020
Debt [Line Items]
Line of credit maximum borrowing amount	$ 50
Line of credit facility remaining	45
Line of Credit Facility, Borrowing Capacity, Description		The second tranche of $20.0 million would be available upon request by the Company and Lenders approval until August 31, 2022, and the third tranche, $25.0 million, would be available at the Company's request subject Lenders' discretion. As of March 31, 2022, neither tranche had been requested.
SVB Loan Agreement [Member]
Debt [Line Items]
Debt Instrument, Face Amount				$ 5
Silicon Valley Bank ("SVB") and Oxford Finance LLC ("Oxford") [Member]
Debt [Line Items]
Line of credit maximum borrowing amount	50
Silicon Valley Bank [Member]
Debt [Line Items]
Line of credit maximum borrowing amount	50
Repayments of Long-term Lines of Credit	5
Silicon Valley Bank [Member] | Maximum [Member]
Debt [Line Items]
Prepayment fee percentage		2.00%
Silicon Valley Bank [Member] | Minimum [Member]
Debt [Line Items]
Prepayment fee percentage		1.00%
Tranche One [Member]
Debt [Line Items]
Line of credit facility remaining	20
Tranche Two [Member]
Debt [Line Items]
Line of credit facility remaining	25
Contract Termination [Member] | Silicon Valley Bank [Member]
Debt [Line Items]
Termination of Loan and Security agreement	$ 15
Term Loan Agreement [Member] | Silicon Valley Bank [Member]
Debt [Line Items]
Line of credit maximum borrowing amount				$ 15
Debt instrument, maturity date		Nov. 1, 2026
Debt Instrument, Interest Rate		4.90%
Debt instrument final payment interest fee percentage		5.00%
Fee incurred for undrawn portion of loan		3.00%
Term Loan Agreement [Member] | Silicon Valley Bank [Member] | SVB Loan Agreement [Member]
Debt [Line Items]
Debt instrument, maturity date		Jul. 1, 2024
Debt Instrument, Interest Rate			6.75%
Debt instrument final payment interest fee percentage		7.00%
Prepayment fee percentage		0.00%
Term Loan Agreement [Member] | Silicon Valley Bank [Member] | Prime Rate [Member]
Debt [Line Items]
Debt Instrument, Interest Rate During Period		8.15%
Term Loan Agreement [Member] | Silicon Valley Bank [Member] | Prime Rate [Member] | SVB Loan Agreement [Member]
Debt [Line Items]
Debt Instrument, Interest Rate		6.75%
Term Loan Agreement [Member] | Silicon Valley Bank [Member] | Maximum [Member] | SVB Loan Agreement [Member]
Debt [Line Items]
Debt Instrument, Interest Rate		10.00%
Prepayment fee percentage		2.00%
Term Loan Agreement [Member] | Silicon Valley Bank [Member] | Minimum [Member] | SVB Loan Agreement [Member]
Debt [Line Items]
Prepayment fee percentage		1.00%
Term Loan Agreement [Member] | Silicon Valley Bank [Member] | Minimum [Member] | Prime Rate [Member] | SVB Loan Agreement [Member]
Debt [Line Items]
Debt Instrument, Interest Rate		3.50%

Debt - Summary of Future Minimu

Debt - Summary of Future Minimum Payments Under Loan Facility (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
2022 (remaining)	$ 0
2023	0
2024	1,714
2025	1,714
Thereafter	1,572
Total Future minimum payments	5,000
Unamortized discount	(159)
Total, net	$ 4,841	$ 4,819

Merger - Additional Information

Merger - Additional Information (Detail) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)$ / sharesshares
Business Acquisition [Line Items]
Estimated Fair value of total consideration | $	$ 103.4
Transaction costs | $	$ 1.6
Common Stock [Member]
Business Acquisition [Line Items]
Number of shares of common stock outstanding prior to the merger date	5,173,772
Shares issuable upon conversion of preferred stock [Member]
Business Acquisition [Line Items]
Number of shares of convertible preferred stock outstanding prior to merger	10,248
Common Stock Convertible Basis [Member]
Business Acquisition [Line Items]
Number of shares of Common stock as a convertible basis outstanding prior to merger	292,799
Sunesis Pharmaceuticals Inc [Member]
Business Acquisition [Line Items]
Share price | $ / shares	$ 18.62

Merger - Summary of Allocation

Merger - Summary of Allocation of the Purchase Price To Assets and Liabilities Acquired (Detail) $ in Thousands	Mar. 31, 2022USD ($)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Net assets acquired	$ 18,956
Acquired IPR&D	84,478
Purchase price	103,434
Net assets acquired
Cash and cash equivalents	17,143
Prepaid expenses and other assets	3,768
Accounts payable and accrued liabilities	(1,955)
Net assets acquired	$ 18,956

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	May 28, 2021	Feb. 24, 2021	Jan. 01, 2020	Jan. 31, 2017	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Jul. 30, 2020
Stockholders Equity [Line Items]
Common stock, shares outstanding					37,486,177		37,424,863
Convertible Preferred Stock, Shares Issued upon Conversion								18,811,552
Preferred stock, shares authorized					10,000,000
Shares Issued					0
Preferred stock, shares outstanding					10,248		10,248
Share of common stock value					$ 25,000
Weighted average exercise price					$ 6.13		$ 7.33
Stock reserved for future grant					8,240,586		6,429,819
Stock-based compensation					$ 1,772,000	$ 644,000
Stock option plan weighted average vesting period					9 years 1 month 6 days		8 years 10 months 24 days
Twenty Thousand and Sixteen Equity Incentive Plan [Member]
Stockholders Equity [Line Items]
Options granted period					10 years
2021 Equity Incentive Plan [Member]
Stockholders Equity [Line Items]
Common stock available for issuance automatic increase period			10 years
Shares of common stock available for issuance			3,771,428		2,628,571
Shares Available for Issuance					985,358
Shares Available for Future Grant					84,591
Purchase price of a share as a percentage of fair market value					100.00%
Stock Options Granted					10 years
Percentage Of Nonqualified Options Exercisable Price Of Fair Market Value Of Common Stock					100.00%
Weighted average exercise price					$ 28.18
2021 Inducement Plan [Member]
Stockholders Equity [Line Items]
Shares of common stock available for issuance					515,000
Stock reserved for future grant					1,000,000
Stock Options [Member]
Stockholders Equity [Line Items]
Stock-based compensation					$ 1,600,000	500,000
Stock option plan weighted average vesting period					3 years
Unrecognised compensation expense related to unvested units					$ 19,200,000
Incentive Stock Options [Member] | Twenty Thousand and Sixteen Equity Incentive Plan [Member]
Stockholders Equity [Line Items]
Percentage of exercise price fair value				100.00%
Nonqualified Options [Member] | Twenty Thousand and Sixteen Equity Incentive Plan [Member]
Stockholders Equity [Line Items]
Percentage of exercise price fair value				85.00%
Restricted Stock Units [Member]
Stockholders Equity [Line Items]
Stock reserved for future grant					692,408		745,668
Stock-based compensation					$ 200,000	$ 100,000
Unrecognised compensation expense related to unvested units					$ 2,500,000
Restricted Stock units plan weighted average vesting period					3 years 2 months 12 days
Minimum [Member] | Twenty Thousand and Sixteen Equity Incentive Plan [Member]
Stockholders Equity [Line Items]
Options,vesting period					0 years
Maximum [Member]
Stockholders Equity [Line Items]
Stock Options Granted					4 years
Maximum [Member] | Twenty Thousand and Sixteen Equity Incentive Plan [Member]
Stockholders Equity [Line Items]
Options,vesting period					4 years
Series E and Series F Convertible Preferred Stock [Member]
Stockholders Equity [Line Items]
Preferred stock, payment to stock holders in the event of liquidation, dissolution or winding up preference per share					$ 0.0001
Percentage of outstanding common stock					9.98%
Shares issuable upon conversion of preferred stock [Member]
Stockholders Equity [Line Items]
Stock reserved for future grant					292,799		292,799
Series E Convertible Preferred Stock [Member]
Stockholders Equity [Line Items]
Price per common share					$ 500
Preferred stock, shares outstanding					1,915
Convertible share price per share					$ 17.50
Series F Convertible Preferred Stock [Member]
Stockholders Equity [Line Items]
Price per common share					$ 600
Preferred stock, shares outstanding					8,333
Convertible share price per share					$ 21
Warrant [Member] | Preferred Stock Warrants [Member]
Stockholders Equity [Line Items]
Class of warrant or right, exercise price of warrants or rights									$ 0.6055
Issue of warrants exercisable									206,440
Warrant [Member] | Preferred Stock Warrants [Member] | Silicon Valley Bank [Member]
Stockholders Equity [Line Items]
Class of warrant or right, exercise price of warrants or rights									$ 5.42
Issue of warrants exercisable									23,100
Common Stock [Member]
Stockholders Equity [Line Items]
Shares Issued					37,486	37,036,000	37,425	906,000
Stock issued during period						5,173,000
Stock Issued During Period, Shares, New Issues						12,012,000
Common Stock [Member] | Common Warrants [Member]
Stockholders Equity [Line Items]
Class of warrant or right, exercise price of warrants or rights					$ 0.09			$ 0.09
Class of warrant or right issued in period of warrants or rights					250,323			250,323
Class of warrant or right issued remain unexercised					86,209
Warrant expiration period					7 years
Employee Stock Purchase Plan [Member]
Stockholders Equity [Line Items]
Shares Available for Future Grant					60,948
Purchase price of a share as a percentage of fair market value					85.00%
Duration of offering period					12 months
Duration of each purchase period					6 months
Stock reserved for future grant					60,948		60,948
Private Placement [Member] | Common Stock [Member]
Stockholders Equity [Line Items]
Proceeds from issuance initial public offering		$ 65,000,000
Adjustments to additional paid in capital stock issuance costs		$ 2,700,000
Stock Issued During Period, Shares, New Issues		12,012,369
Sales Agreement [Member]
Stockholders Equity [Line Items]
Common stock par value	$ 0.0001
Legal and accounting cost					$ 100,000
Sales Agreement [Member] | Maximum [Member]
Stockholders Equity [Line Items]
Potential sales of common stock	$ 50,000,000

Stockholders' Equity - Shares o

Stockholders' Equity - Shares of Common Stock Reserved for Future Issuance (Detail) - shares	Mar. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Total common stock reserved for future issuance	8,240,586	6,429,819
Authorized for future option grants [Member]
Class of Stock [Line Items]
Total common stock reserved for future issuance	1,500,358	1,169,523
Common stock warrants [Member]
Class of Stock [Line Items]
Total common stock reserved for future issuance	109,309	109,309
Common stock authorized for the ESPP [Member]
Class of Stock [Line Items]
Total common stock reserved for future issuance	60,948	60,948
Stock options issued and outstanding for all plans [Member]
Class of Stock [Line Items]
Total common stock reserved for future issuance	5,584,764	4,051,572
RSUs outstanding [Member]
Class of Stock [Line Items]
Total common stock reserved for future issuance	692,408	745,668
Convertible preferred stock
Class of Stock [Line Items]
Total common stock reserved for future issuance	292,799	292,799

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Shared Based Compensation Cost Included in Condensed Statement Of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share Based Compensation Cost Included in Condensed Statement Of Operations [Line Items]
Total stock-based compensation expense	$ 1,772	$ 644
Research and development [Member]
Share Based Compensation Cost Included in Condensed Statement Of Operations [Line Items]
Total stock-based compensation expense	646	307
General and administrative [Member]
Share Based Compensation Cost Included in Condensed Statement Of Operations [Line Items]
Total stock-based compensation expense	$ 1,126	$ 337

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Fair Value of Stock Options is Estimated Using the Black-Scholes Model (Detail)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option term	6 years 3 months 18 days
Expected volatility of common stock		90.20%
Expected dividend yield	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	1.82%	0.66%
Expected option term		5 years 9 months 18 days
Expected volatility of common stock	84.02%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	2.19%	1.09%
Expected option term		6 years 3 months 18 days
Expected volatility of common stock	84.66%

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Stock Option Activity (Detail) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Outstanding, Beginning Balance, Number of Shares	3,964,000
Outstanding, Beginning Balance, Weighted Average Exercise Price Per Share	$ 7.33
Options granted , Numbers of Shares	1,605,000
Options granted, Weighted Average Exercise Price Per Share	$ 3.03
Options exercised , Numbers of Shares	(7,000)
Options exercised, Weighted Average Exercise Price Per Share	$ 0.96
Options Cancelled , Number of Shares	(62,000)
Options Cancelled , Weighted average exercise price	$ 3.27
Outstanding, Ending Balance, Number of Shares	5,500,000	3,964,000
Outstanding, Ending Balance, Weighted Average Exercise Price Per Share	$ 6.13	$ 7.33
Outstanding, Weighted Average Remaining Contractual Term (Years)	9 years 1 month 6 days	8 years 10 months 24 days
2011 Plan [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Outstanding, Ending Balance, Number of Shares	85,000
Outstanding, Ending Balance, Weighted Average Exercise Price Per Share	$ 28.18
Outstanding, Weighted Average Remaining Contractual Term (Years)	3 years 1 month 6 days

Stockholders' Equity - Summar_4

Stockholders' Equity - Summary of Restricted Stock Units Activity (Detail)	3 Months Ended
	Mar. 31, 2022$ / sharesshares
Share-based Payment Arrangement [Abstract]
RSUs, Beginning balance | shares	745,000
RSUs, Granted | shares	0
RSUs, Vested | shares	53,000
RSUs, Cancelled | shares	0
RSUs, Ending balance | shares	692,000
Weighted Average Grant Date Fair Value per Share, Beginning balance | $ / shares	$ 4.22
Weighted Average Grant Date Fair Value per Share, Granted | $ / shares	0
Weighted Average Grant Date Fair Value per Share, Vested | $ / shares	4.22
Weighted Average Grant Date Fair Value per Share, Cancelled | $ / shares	0
Weighted Average Grant Date Fair Value per Share, Ending balance | $ / shares	$ 4.22
Weighted Average Remaining Contractual Term (Years)	3 years 2 months 12 days

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Aug. 31, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
Lease liability			$ 567,000
Operating lease right-of-use asset			549,000		$ 640,000
Operating Lease Expense			104,000	$ 71,000
Lease liability noncurrent			175,000		$ 278,000
Cash paid for operating lease liability			$ 105,000	$ 99,000
Operating lease weighted average discount rate						8.00%
Operating lease weighted average remaining lease term			1 year 4 months 24 days
Option to extend the lease		option for an additional year
Noncancelable operating lease agreement [Member] | Amended Operating Lease [Member]
Loss Contingencies [Line Items]
Lease liability		$ 667,000
Operating lease right-of-use asset		$ 667,000
Description of Lease Term		August 2023
Percentage of increase in monthly base rent		4.00%
Additional noncancelable operating lease agreement [Member] | New Operating Lease [Member]
Loss Contingencies [Line Items]
Lease liability	$ 439,000
Operating lease right-of-use asset	$ 439,000
Description of Lease Term	August 2020 through August 2023
Lease extended termination description	option to terminate the lease prior to its expiration with at least one month’s prior written notice and a one-time payment equal to four months’ rent.
Option to extend the lease	option for an additional year
Maximum [Member] | Noncancelable operating lease agreement [Member] | Amended Operating Lease [Member]
Loss Contingencies [Line Items]
Operating Leases Rent Expense		$ 21,444
Maximum [Member] | Additional noncancelable operating lease agreement [Member] | New Operating Lease [Member]
Loss Contingencies [Line Items]
Lease rental rate per month	$ 14,033
Percentage of increase in monthly base rent	9.00%
Minimum [Member] | Noncancelable operating lease agreement [Member] | Amended Operating Lease [Member]
Loss Contingencies [Line Items]
Operating Leases Rent Expense		$ 20,019
Minimum [Member] | Additional noncancelable operating lease agreement [Member] | New Operating Lease [Member]
Loss Contingencies [Line Items]
Lease rental rate per month	$ 12,462
Percentage of increase in monthly base rent	4.00%

Subsequent Events (Additional I

Subsequent Events (Additional Information) (Details) $ in Millions	Nov. 04, 2021USD ($)
Subsequent Event [Line Items]
Line of credit maximum borrowing amount	$ 50
Line of credit facility remaining	45
Tranche One [Member]
Subsequent Event [Line Items]
Line of credit facility remaining	20
Tranche Two [Member]
Subsequent Event [Line Items]
Line of credit facility remaining	25
Silicon Valley Bank ("SVB") and Oxford Finance LLC ("Oxford") [Member]
Subsequent Event [Line Items]
Line of credit maximum borrowing amount	50
Line of credit facility remaining	45
Silicon Valley Bank ("SVB") and Oxford Finance LLC ("Oxford") [Member] | Tranche Two [Member]
Subsequent Event [Line Items]
Line of credit facility remaining	$ 20