Apexigen (APGN) S-1/A 1 Sep 22 IPO registration (amended) Financial data

Cover Page

Cover Page	6 Months Ended
	Jun. 30, 2022
Document Information [Line Items]
Document Type	S-1/A
Amendment Flag	true
Amendment Description	AMENDMENT NO. 1
Entity Registrant Name	Apexigen, Inc.
Entity Central Index Key	0001814140
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 11,644	$ 23,443	$ 25,284
Short-term investments	9,981	12,917	35,182
Prepaid expenses and other current assets	3,378	1,681	887
Total current assets	25,003	38,041	61,353
Property and equipment, net	190	245	309
Right-of-use assets	294	483	1,124
Other assets	331	327	59
Total assets	25,818	39,096	62,845
Current liabilities:
Accounts payable	7,704	4,487	3,522
Accrued liabilities	7,497	8,488	6,597
Deferred revenue	4,601	3,610	1,887
Lease liabilities, current portion	312	369	614
Total current liabilities	20,114	16,954	12,620
Lease liabilities, less current portion	0	141	542
Total liabilities	20,114	17,095	13,162
Commitment and contingencies (Note 10)
Convertible preferred stock	158,707	158,707	158,707
Stockholders' deficit:
Common Stock	31	31	31
Additional paid-in capital	8,853	7,991	6,750
Accumulated deficit	(161,870)	(144,724)	(115,808)
Accumulated other comprehensive income (loss)	(17)	(4)	3
Total stockholders' deficit	(153,003)	(136,706)	(109,024)
Total liabilities, convertible preferred stock and stockholders' deficit	$ 25,818	$ 39,096	$ 62,845

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Convertible preferred stock, Shares Authorized	148,570,771	148,570,771	148,570,771
Convertible preferred stock, Shares Issued	145,130,628	145,130,628	145,130,628
Convertible preferred stock, Shares Outstanding	145,130,628	145,130,628	145,130,628
Convertible preferred stock, Liquidation Preference	$ 160,085	$ 160,085	$ 160,085
Common stock, par value	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized	230,000,000	230,000,000	230,000,000
Common stock, shares issued	31,461,489	31,070,665	30,521,693
Common stock, shares outstanding	31,461,489	31,070,665	30,521,693
Convertible Preferred Stock [Member]
Convertible preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Convertible preferred stock, Shares Authorized	148,570,771	148,570,771	148,570,771
Convertible preferred stock, Shares Issued	145,130,628	145,130,628	145,130,628
Convertible preferred stock, Shares Outstanding	145,130,628	145,130,628	145,130,628
Convertible preferred stock, Liquidation Preference	$ 160,085	$ 160,085

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 6,005	$ 4,658	$ 13,113	$ 9,621	$ 21,664	$ 18,770
General and administrative	2,139	2,389	4,124	3,928	7,293	5,774
Total operating expenses	8,144	7,047	17,237	13,549	28,957	24,544
Loss from operations	(8,144)	(7,047)	(17,237)	(13,549)	(28,957)	(24,544)
Interest income, net	40	12	91	27	41	421
Net loss	$ (8,104)	$ (7,035)	$ (17,146)	$ (13,522)	$ (28,916)	$ (24,123)
Net loss per share attributable to common stockholders, Basic	$ (0.26)	$ (0.23)	$ (0.55)	$ (0.44)	$ 0.94	$ 0.79
Net loss per share attributable to common stockholders, Diluted	$ (0.26)	$ (0.23)	$ (0.55)	$ (0.44)	$ 0.94	$ 0.79
Weighted-average common shares used to compute net loss per share, Basic	31,454,265	30,910,694	31,425,054	30,781,596	30,901,032	30,512,368
Weighted-average common shares used to compute net loss per share, Diluted	31,454,265	30,910,694	31,425,054	30,781,596	30,901,032	30,512,368
Comprehensive Loss:
Net loss	$ (8,104)	$ (7,035)	$ (17,146)	$ (13,522)	$ (28,916)	$ (24,123)
Other comprehensive loss
Unrealized gain (loss) on marketable securities	(15)	4	(13)	(2)	(7)	5
Comprehensive loss	$ (8,119)	$ (7,031)	$ (17,159)	$ (13,524)	$ (28,923)	$ (24,118)

Condensed Statements of Convert

Condensed Statements of Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Convertible Preferred Stock [Member]
Beginning balance (Shares) at Dec. 31, 2019						136,528,546
Beginning balance at Dec. 31, 2019						$ 145,434
Beginning balance (Shares) at Dec. 31, 2019		30,497,526
Beginning balance at Dec. 31, 2019	$ (86,266)	$ 30	$ 5,391	$ (91,685)	$ (2)
Issuance of Series C convertible preferred stock, net of issuance costs of $58 (Shares)						8,602,082
Issuance of Series C convertible preferred stock, net of issuance costs of $58						$ 13,273
Exercise of stock options (Shares)		24,167
Exercise of stock options	15	$ 1	14
Stock-based compensation	1,345		1,345
Net loss	(24,123)			(24,123)
Other comprehensive gain (loss)	$ 5				5
Ending balance (Shares) at Dec. 31, 2020	145,130,628					145,130,628
Ending balance at Dec. 31, 2020	$ 158,707					$ 158,707
Ending balance (Shares) at Dec. 31, 2020		30,521,693
Ending balance at Dec. 31, 2020	(109,024)	$ 31	6,750	(115,808)	3
Exercise of stock options (Shares)		388,972
Exercise of stock options	24		24
Stock-based compensation	622		622
Net loss	(13,522)			(13,522)
Other comprehensive gain (loss)	(2)				(2)
Ending balance (Shares) at Jun. 30, 2021						145,130,628
Ending balance at Jun. 30, 2021						$ 158,707
Ending balance (Shares) at Jun. 30, 2021		30,910,665
Ending balance at Jun. 30, 2021	$ (121,902)	$ 31	7,396	(129,330)	1
Beginning balance (Shares) at Dec. 31, 2020	145,130,628					145,130,628
Beginning balance at Dec. 31, 2020	$ 158,707					$ 158,707
Beginning balance (Shares) at Dec. 31, 2020		30,521,693
Beginning balance at Dec. 31, 2020	$ (109,024)	$ 31	6,750	(115,808)	3
Exercise of stock options (Shares)	548,972	548,972
Exercise of stock options	$ 98		98
Stock-based compensation	1,143		1,143
Net loss	(28,916)			(28,916)
Other comprehensive gain (loss)	$ (7)				(7)
Ending balance (Shares) at Dec. 31, 2021	145,130,628					145,130,628
Ending balance at Dec. 31, 2021	$ 158,707					$ 158,707
Ending balance (Shares) at Dec. 31, 2021		31,070,665
Ending balance at Dec. 31, 2021	(136,706)	$ 31	7,991	(144,724)	(4)
Beginning balance (Shares) at Mar. 31, 2021						145,130,628
Beginning balance at Mar. 31, 2021						$ 158,707
Beginning balance (Shares) at Mar. 31, 2021		30,910,665
Beginning balance at Mar. 31, 2021	(115,133)	$ 31	7,134	(122,295)	(3)
Stock-based compensation	262		262
Net loss	(7,035)			(7,035)
Other comprehensive gain (loss)	4				4
Ending balance (Shares) at Jun. 30, 2021						145,130,628
Ending balance at Jun. 30, 2021						$ 158,707
Ending balance (Shares) at Jun. 30, 2021		30,910,665
Ending balance at Jun. 30, 2021	$ (121,902)	$ 31	7,396	(129,330)	1
Beginning balance (Shares) at Dec. 31, 2021	145,130,628					145,130,628
Beginning balance at Dec. 31, 2021	$ 158,707					$ 158,707
Beginning balance (Shares) at Dec. 31, 2021		31,070,665
Beginning balance at Dec. 31, 2021	(136,706)	$ 31	7,991	(144,724)	(4)
Exercise of stock options (Shares)		390,824
Exercise of stock options	73		73
Stock-based compensation	789		789
Net loss	(17,146)			(17,146)
Other comprehensive gain (loss)	$ (13)				(13)
Ending balance (Shares) at Jun. 30, 2022	145,130,628					145,130,628
Ending balance at Jun. 30, 2022	$ 158,707					$ 158,707
Ending balance (Shares) at Jun. 30, 2022		31,461,489
Ending balance at Jun. 30, 2022	(153,003)	$ 31	8,853	(161,870)	(17)
Beginning balance (Shares) at Mar. 31, 2022						145,130,628
Beginning balance at Mar. 31, 2022						$ 158,707
Beginning balance (Shares) at Mar. 31, 2022		31,395,489
Beginning balance at Mar. 31, 2022	(145,275)	$ 31	8,462	(153,766)	(2)
Exercise of stock options (Shares)		66,000
Exercise of stock options	23		23
Stock-based compensation	368		368
Net loss	(8,104)			(8,104)
Other comprehensive gain (loss)	$ (15)				(15)
Ending balance (Shares) at Jun. 30, 2022	145,130,628					145,130,628
Ending balance at Jun. 30, 2022	$ 158,707					$ 158,707
Ending balance (Shares) at Jun. 30, 2022		31,461,489
Ending balance at Jun. 30, 2022	$ (153,003)	$ 31	$ 8,853	$ (161,870)	$ (17)

Condensed Statements of Conve_2

Condensed Statements of Convertible Preferred Stock and Stockholders' Deficit (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Series C Convertible Preferred Stock [Member]
Issaunce Costs	$ 58

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (17,146)	$ (13,522)	$ (28,916)	$ (24,123)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	55	53	105	127
Stock-based compensation	789	622	1,143	1,345
Accretion of discount and amortization of premiums on marketable securities	7	111	204	127
Non-cash lease expense	200	322	522	829
Other	0	6	6	(1)
Changes in current assets and liabilities:
Prepaid expenses and other current assets	82	(767)	(352)	312
Other assets	(104)	(110)	(168)	0
Accounts payable	2,058	(708)	841	813
Accrued expenses	(865)	122	1,521	(444)
Deferred revenue	991	764	1,723	1,887
Lease liabilities	(209)	(325)	(531)	(829)
Net cash used in operating activities	(14,142)	(13,432)	(23,902)	(19,957)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(43)	(54)	(54)	0
Purchases of marketable securities	(14,985)	(20,179)	(20,179)	(67,344)
Sales of marketable securities	17,947	30,530	42,257	43,183
Net cash provided by investing activities	2,919	10,297	22,024	(24,161)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of deferred transaction costs	(649)	0	(61)	(280)
Proceeds from exercise of stock options	73	24	98	15
Proceeds from issuance of convertible preferred stock, net of issuance costs			0	13,162
Net cash provided by (used in) financing activities	(576)	24	37	12,897
Net (decrease) increase in cash and cash equivalents	(11,799)	(3,111)	(1,841)	(31,221)
Cash and cash equivalents, beginning of period	23,443	25,284	25,284	56,505
Cash and cash equivalents, end of period	$ 11,644	$ 22,173	23,443	25,284
NONCASH INVESTING AND FINANCING ACTIVITIES:
Deferred offering costs in other accrued liabilities			364	0
Purchase of equipment included in accounts payable			43	54
Impact of right-of-use assets and lease liabilities upon adoption of ASC 842			$ 0	$ 1,707

Organization and Description of

Organization and Description of the Business	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of the Business	1. Organization and Description of the Business Description of Business Apexigen, Inc. (“Apexigen”) is a clinical-stage biopharmaceutical company focused on discovering and developing antibody therapeutics for oncology, with an emphasis on new immuno-oncology agents designed to harness the patient’s immune system to combat and eradicate cancer. Apexigen’s lead product candidates are sotigalimab (“sotiga” or “APX005M”), which is a CD40 agonist antibody, and APX601, which is a TNFR2 antagonist antibody. Apexigen also has out-license out-licensed out-licensed spun-out spun-out On March 17, 2022, Brookline Capital Acquisition Corp. (“BCAC”) and Apexigen entered into a business combination agreement (“Business Combination Agreement”) pursuant to which BCAC and Apexigen agreed to combine, with the former equityholders of both entities holding equity in the combined public company listed on the Nasdaq Stock Exchange and with Apexigen’s existing equityholders owning a majority of the equity in the combined public company. Existing Apexigen equityholders received equity in the combined public company in the form of common shares and warrants. Under the Business Combination Agreement, the transaction valued Apexigen at $205.0 million on a fully diluted basis, net of exercise proceeds for Apexigen’s pre-closing options. The Transaction closed on July 29, 2022. As a result, the combined public company received approximately $19.0 million in gross proceeds funded by approximately $4.5 million in cash held in BCAC’s trust account net of redemption and $14.5 million from the PIPE. The combined public company incurred $8.9 million in transaction expenses relating to the Transaction, consisting of banking, legal, and other professional fees. The PIPE investors receive an aggregate of 1,452,000 units (each a “PIPE Unit”) at a purchase price of $10.00 per unit. Each PIPE Unit consists of one share of BCAC Common Stock and one-half of Liquidity and Capital Resources As of June 30, 2022, Apexigen had approximately $21.6 million of cash, cash equivalents, and short-term investments. Apexigen has incurred substantial losses and negative cash flows from operations since inception and had an accumulated deficit of $161.9 million as of June 30, 2022. Since inception through June 30, 2022, Apexigen has funded operations primarily through the issuance of convertible preferred stock, proceeds from collaborative research and development agreements, and borrowings under a debt arrangement. Due to Apexigen’s significant research, development and manufacturing expenditures, Apexigen has generated operating losses in all periods presented. Apexigen expects to incur substantial additional losses in the future as Apexigen advances and expands its research and development activities and prepares to pursue the potential regulatory approval and commercialization of its product candidates. Based on Apexigen’s research and development activities and plans, there is uncertainty regarding the ability to maintain liquidity sufficient to operate the business effectively, which raises substantial doubt as to the ability to continue as a going concern. Apexigen may seek additional funds through the sale and issuance of shares of Apexigen’s common stock in private or public offerings, other equity or debt financings, collaborations or partnerships with third parties, or other transactions to monetize assets, including Apexigen’s right to receive milestone payments and royalties under Apexigen’s out-license To the extent that Apexigen raises additional capital through strategic alliances, licensing arrangements or other monetization transactions with third parties, Apexigen may have to relinquish valuable rights to Apexigen’s product candidates, future revenue streams or research programs or grant licenses on terms that may not be favorable to us. If Apexigen raises additional capital through public or private equity offerings, the ownership interest of the then-existing stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect Apexigen’s stockholders’ rights. If Apexigen raises additional capital through debt financing, Apexigen may be subject to covenants limiting or restricting the ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. Coronavirus Pandemic The ongoing COVID-19 COVID-19 Apexigen cannot predict the specific extent, duration, or full impact that the COVID-19 COVID-19 COVID-19 cannot be predicted. If the financial markets or the overall economy are impacted for an extended period, Apexigen’s business may be significantly adversely affected.	1. Organization and Description of the Business Description of Business Apexigen, Inc. (“Apexigen”) is a clinical-stage biopharmaceutical company focused on discovering and developing antibody therapeutics for oncology, with an emphasis on new immuno-oncology agents that may harness the patient’s immune system to combat and eradicate cancer. Apexigen’s lead product candidates are sotigalimab (“sotiga” or “APX005M”), which is a CD40 agonist antibody, and APX601, which is a TNFR2 antagonist antibody. Apexigen also has out-license out-licensed out-licensed spun-out spun-out Liquidity and Capital Resources As of December 31, 2021, Apexigen had approximately $36.4 million of cash, cash equivalents, and short-term investments. Apexigen has incurred substantial losses and negative cash flows from operations since inception and had an accumulated deficit of $144.7 million as of December 31, 2021. Since inception through December 31, 2021, Apexigen has funded operations primarily through the issuance of convertible preferred stock, proceeds from collaborative research and development agreements, and borrowings under a debt arrangement. Due to Apexigen’s significant research, development and manufacturing expenditures, Apexigen has generated operating losses in all periods presented. Apexigen expects to incur substantial additional losses in the future as Apexigen advances and expands its research and development activities and prepares to pursue the potential regulatory approval and commercialization of its product candidates. Based on Apexigen’s research and development activities and plans, there is uncertainty regarding the ability to maintain liquidity sufficient to operate the business effectively, which raises substantial doubt as to the ability to continue as a going concern. Apexigen may seek additional funds through the sale and issuance of shares of Apexigen’s common stock in private or public offerings, other equity or debt financings, collaborations or partnerships with third parties, or other transactions to monetize assets, including Apexigen’s right to receive milestone payments and royalties under Apexigen’s out-license To the extent that Apexigen raises additional capital through strategic alliances, licensing arrangements or other monetization transactions with third parties, Apexigen may have to relinquish valuable rights to Apexigen’s product candidates, future revenue streams or research programs or grant licenses on terms that may not be favorable to us. If Apexigen raises additional capital through public or private equity offerings, the ownership interest of the then-existing stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect Apexigen’s stockholders’ rights. If Apexigen raises additional capital through debt financing, Apexigen may be subject to covenants limiting or restricting the ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. Coronavirus Pandemic In March 2020, the World Health Organization declared the COVID-19 COVID-19 Apexigen has taken a number of measures to monitor and mitigate the effects of COVID-19 Apexigen cannot predict the specific extent, duration, or full impact that the COVID-19 COVID-19 SARS-CoV-2 COVID-19

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Unaudited Interim Financial Statements The condensed balance sheet as of June 30, 2022, the condensed statements of operations and comprehensive loss for the three and six months ended June 30, 2021 and 2022, the condensed statements of convertible preferred stock and stockholders’ deficit for the three and six months ended June 30, 2021 and 2022, and the condensed statements of cash flows for the six months ended June 30, 2021 and 2022 are unaudited. The unaudited condensed financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal, recurring adjustments that are necessary to present fairly Apexigen’s financial position as of June 30, 2022, its results of operations for the three and six months ended June 30, 2021 and 2022 and its cash flows for the six months ended June 30, 2021 and 2022. The financial data and the other financial information contained in these notes to the condensed financial statements related to the three and six month periods are also unaudited. The condensed balance sheet as of December 31, 2021, is derived from Apexigen’s audited financial statements. The results of operations for the three and six months ended June 30, 2022, are not necessarily indicative of the results to be expected for the year ending December 31, 2022, or for any other future annual or interim period. These condensed financial statements are not complete and are to be read in conjunction with Apexigen’s audited financial statements and the related notes for the year ended December 31, 2021. Basis of Presentation Apexigen prepares the financial statements and accompanying notes in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Emerging Growth Company Apexigen is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), and it may take advantage of certain exemptions from various reporting requirements that are applicable to public companies that are not emerging growth companies. Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that an emerging growth company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging growth Use of Estimates The preparation of 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 financial statements and the reported amounts expensed during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to accruals for research and development costs, stock-based compensation, uncertain tax positions and fair values of common stock and preferred stock. Apexigen adjusts such estimates and assumptions when facts and circumstances dictate. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods. As future events and their effects cannot be determined with precision, actual results could materially differ from those estimates and assumptions.​​​​​​​ Segment Reporting Apexigen has one Cash and Cash Equivalents Apexigen considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market funds and corporate debt securities. The carrying amount of cash equivalents approximates their fair value. Short-Term Investments Short-term investments consist of debt securities with original maturities of greater than three months from the date of purchase but less than one year from the balance sheet date. Such investments are considered available-for-sale Fair Value Measurements Apexigen applies fair value accounting to all financial assets and liabilities and non-financial Concentrations of Credit and Other Risks Financial instruments that potentially subject Apexigen to a concentration of credit risk consist primarily of cash and cash equivalents and short-term investments. Apexigen holds its bank deposits at accredited financial institutions and these deposits may at times exceed insured limits. Apexigen is exposed to credit risk in the event of a default by the financial institutions holding its cash and cash equivalents to the extent of the amounts held in excess of federally insured limits. Apexigen limits its credit risk associated with cash and cash equivalents by placing them with financial institutions it believes are of high quality. Apexigen has not experienced any losses on its deposits of cash. Apexigen’s investment policy limits investments to certain types of securities issued by the U.S. government, its agencies and institutions with investment-grade credit ratings and places restrictions on maturities and concentration by type and issuer. As of June 30, 2021 and 2022, Apexigen had no off-balance Apexigen is subject to a number of risks similar to other early-stage biopharmaceutical companies, including the need to obtain adequate additional funding, possible failure of clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of Apexigen’s products, and protection of proprietary technology. If Apexigen does not successfully develop, obtain regulatory approval for, commercialize or partner its product candidates, it will be unable to generate revenue from product sales or achieve profitability. Property and Equipment, Net Property and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets. The estimated useful life of laboratory equipment, furniture and fixtures, office equipment, and software ranges from t w o Impairment of Long-Lived Assets Apexigen’s long-lived assets are comprised principally of its property and equipment and right-of-use Deferred Transaction Costs Deferred transaction costs consist of direct legal, accounting, filing and other fees and costs directly attributable to the anticipated Transaction (see Note 1). Apexigen will offset any deferred transaction costs against the proceeds received upon the closing of the Transaction. Apexigen capitalized and included in prepaid expenses and other current assets deferred transaction costs of $0.5 million and $2.3 million on the balance sheets as of December 31, 2021 and June 30, 2022, respectively. Revenue Recognition Under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers Apexigen may also earn contingent fees, including milestone payments based on counterparty performance and royalties on sales, from collaborations and other out-license significant risk of reversal. Apexigen will recognize sales-based royalties as revenue when the underlying sales occur. In October 2019, Novartis’ Beovu ® Leases Apexigen determines if an arrangement is a lease at inception and if so, determines whether the lease qualifies as an operating or a finance lease. Apexigen includes operating leases in operating lease right-of-use Apexigen leases its facilities under non-cancelable non-cancellable Research and Development Expenses Research and development costs are expensed as incurred. Research and development expenses are primarily for the development of sotiga, Apexigen’s lead product candidate, as well as APX601 and other product candidates. Research and development costs consist primarily of external costs related to clinical development, contract manufacturing, preclinical development and discovery as well as personnel costs and allocated overhead, such as rent, equipment, depreciation and utilities. Personnel costs consist of salaries, employee benefits and stock-based compensation. Apexigen estimates external research and development expenses based on the services performed, pursuant to contracts with commercial and academic institutions that conduct and manage research and development services on its behalf. Apexigen records the costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued liabilities in the balance sheets. These costs are a component of Apexigen’s research and development expenses. Apexigen accrues for these costs based on factors such as the number of patient visits, the number of active patients, the number of patients enrolled, estimates of the work completed and other measures in accordance with agreements established with its third-party service providers under the service agreements. As actual costs become known, Apexigen adjusts its accrued liabilities. Apexigen has not experienced any significant differences between accrued costs and actual costs incurred. However, the status and timing of actual services performed may vary from Apexigen’s estimates, resulting in adjustments to expense in future periods. Changes in these estimates that result in significant changes to Apexigen’s accruals could significantly affect Apexigen’s results of operations. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized and then expensed as the related goods are delivered or the services are performed. Apexigen evaluates such payments for current or long-term classification based on when they will be realized. Preferred Stock Warrant Liability Apexigen records at fair value freestanding puttable or redeemable warrants, or warrants which are not considered to be indexed to Apexigen’s stock and includes this amount in accrued expenses on Apexigen’s balance sheets. Apexigen adjusts the carrying value of such warrants to their estimated fair value at the end of each reporting period based upon the value of Apexigen’s convertible preferred stock. Convertible Preferred Stock Apexigen records convertible preferred stock at its issuance price less issuance costs on the dates of issuance. Upon the occurrence of certain change in control events that are outside Apexigen’s control, including liquidation, sale or transfer of Apexigen, holders of the convertible preferred stock can cause redemption for cash. Apexigen classifies convertible preferred stock outside of stockholders’ deficit on the balance sheets as events triggering the liquidation preferences are not solely within Apexigen’s control. Apexigen adjusts the carrying values of the convertible preferred stock to their liquidation preferences when and if it becomes probable that such an event will occur. No adjustments have been recorded as of December 31, 2021 or June 30, 2022. Stock-Based Compensation Apexigen measures all stock-based awards granted to employees and non-employees Apexigen uses the Black-Scholes option-pricing model to estimate the fair value of stock option awards and recognizes expense using the straight-line attribution approach. The Black-Scholes option-pricing model requires assumptions to be made related to the fair value of Apexigen’s common stock, the expected term of the awards, expected stock priced volatility, risk-free rate for a period that approximates the expected term of the awards and the expected dividend yield. Income Taxes Apexigen accounts for income taxes under the asset and liability method. Under this method, Apexigen recognizes deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Apexigen measures deferred tax assets and liabilities using enacted tax rates applied to taxable income in the years in which Apexigen expects to realize those temporary differences. Apexigen recognizes the effect on deferred tax assets and liabilities of a change in tax rates as income or loss in the period that includes the enactment date. Apexigen establishes a valuation allowance, when necessary, to reduce deferred tax assets to the amount we expect to realize. Apexigen recognizes financial statement effects of uncertain tax positions when it is more-likely-than-not, Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ deficit that are excluded from net loss, primarily unrealized gains or losses on Apexigen’s marketable securities. Net Loss per Share Apexigen calculates basic net loss per share by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented, since the effects of potentially dilutive securities are antidilutive given Apexigen’s net loss. Recent Accounting Pronouncements The adoption dates discussed below reflect the election as an emerging growth company. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments off-balance held-to-maturity available-for-sale	2. Summary of Significant Accounting Policies Basis of Presentation Apexigen prepares the financial statements and accompanying notes in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Emerging Growth Company Apexigen is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), and it may take advantage of certain exemptions from various reporting requirements that are applicable to public companies that are not emerging growth companies. Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that an emerging growth company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging growth Use of Estimates The preparation of 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 financial statements and the reported amounts expensed during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to accruals for research and development costs, stock-based compensation and uncertain tax positions. Actual results could differ from those estimates. Segment Reporting Apexigen has one operating segment, which is the business of researching, developing and commercializing antibody therapeutics for oncology. Apexigen’s chief operating decision maker, its Chief Executive Officer, manages Apexigen’s operations on an aggregated basis for the purposes of allocating resources and evaluating financial performance. Cash and Cash Equivalents Apexigen considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market funds, commercial paper, U.S. government and corporate securities. The carrying amount of cash equivalents approximates their fair value. Short-Term Investments Short-term investments consist of debt securities with original maturities of greater than three months from the date of purchase but less than one year from the balance sheet date. Such investments are considered available-for-sale Fair Value Measurements Apexigen applies fair value accounting to all financial assets and liabilities and non-financial Concentrations of Credit and Other Risks Financial instruments that potentially subject Apexigen to a concentration of credit risk consist primarily of cash and cash equivalents and short-term investments. Apexigen holds Apexigen’s bank deposits at accredited financial institutions and these deposits may at times exceed insured limits. Apexigen is exposed to credit risk in the event of a default by the financial institutions holding its cash and cash equivalents to the extent of the amounts held in excess of federally insured limits. Apexigen limits its credit risk associated with cash and cash equivalents by placing them with financial institutions it believes are of high quality. Apexigen has not experienced any losses on its deposits of cash. Apexigen’s investment policy limits investments to certain types of securities issued by the U.S. government, its agencies and institutions with investment-grade credit ratings and places restrictions on maturities and concentration by type and issuer. As of December 31, 2020 and 2021, Apexigen had no off-balance Apexigen is subject to a number of risks similar to other early-stage biopharmaceutical companies, including the need to obtain adequate additional funding, possible failure of clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of Apexigen’s products, and protection of proprietary technology. If Apexigen does not successfully develop, obtain regulatory approval for, commercialize or partner its product candidates, it will be unable to generate revenue from product sales or achieve profitab ili Property and Equipment, Net Property and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets. The estimated useful life of laboratory equipment, furniture and fixtures, office equipment, and software ranges from t w o Impairment of Long-Lived Assets Apexigen’s long-lived assets are comprised principally of its property and equipment and right-of-use Deferred Offering Costs Deferred offering costs consist of direct legal, accounting, filing and other fees and costs directly attributable to an anticipated equity offering. Apexigen will offset any deferred offering costs against the proceeds received upon the closing of the Transaction (see Note 13). Apexigen capitalized and included in prepaid expenses and other current assets deferred offering costs of $0.4 million on the balance sheet as of December 31, 2021. Revenue Recognition Under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers Apexigen may also earn contingent fees, including milestone payments based on counterparty performance and royalties on sales, from collaborations and other out-license ® Leases Apexigen determines if an arrangement is a lease at inception and if so, determines whether the lease qualifies as an operating or a finance lease. Apexigen includes operating leases in operating lease right-of-use Apexigen leases its facilities under non-cancelable non-cancellable Research and Development Expenses Research and development costs are expensed as incurred. Research and development expenses consist primarily of the development of sotiga, Apexigen’s lead product candidate, as well as APX601 and other product candidates. Research and development costs consist primarily of external costs related to clinical development, contract manufacturing, preclinical development and discovery as well as personnel costs and allocated overhead, such as rent, equipment, depreciation and utilities. Personnel costs consist of salaries, employee benefits and stock-based compensation. Apexigen estimates external research and development expenses based on the services performed, pursuant to contracts with commercial and academic institutions that conduct and manage research and development services on its behalf. Apexigen records the costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued liabilities in the balance sheets. These costs are a component of Apexigen’s research and development expenses. Apexigen accrues for these costs based on factors such as the numbers of subject visits, the number of active patients, the number of patients enrolled, and estimates of the work completed and other measures in accordance with agreements established with its third-party service providers under the service agreements. As actual costs become known, Apexigen adjusts its accrued liabilities. Apexigen has not experienced any significant differences between accrued costs and actual costs incurred. However, the status and timing of actual services performed may vary from Apexigen’s estimates, resulting in adjustments to expense in future periods. Changes in these estimates that result in significant changes to Apexigen’s accruals could significantly affect Apexigen’s results of operations. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized and then expensed as the related goods are delivered or the services are performed. Apexigen evaluates such payments for current or long-term classification based on when they will be realized. Preferred Stock Warrant Liability Apexigen records at fair value freestanding puttable or redeemable warrants, or warrants which are not considered to be indexed to Apexigen’s stock and includes this amount in accrued expenses on Apexigen’s balance sheets. Apexigen adjusts the carrying value of such warrants to their estimated fair value at the end of each reporting period based upon the value of Apexigen’s convertible preferred stock. Convertible Preferred Stock Apexigen records convertible preferred stock at its issuance price less issuance costs on the dates of issuance. Upon the occurrence of certain change in control events that are outside Apexigen’s control, including liquidation, sale or transfer of Apexigen, holders of the convertible preferred stock can cause redemption for cash. Apexigen classifies convertible preferred stock outside of stockholders’ deficit on the balance sheets as events triggering the liquidation preferences are not solely within Apexigen’s control. Apexigen adjusts the carrying values of the convertible preferred stock to their liquidation preferences when and if it becomes probable that such an event will occur. Stock-Based Compensation Apexigen measures all stock-based awards granted to employees and non-employees Apexigen uses the Black-Scholes option-pricing model to estimate the fair value of stock option awards and recognizes expense using the straight-line attribution approach. The Black-Scholes option-pricing model requires assumptions to be made related to the fair value of Apexigen’s common stock, the expected term of the awards, expected stock priced volatility, risk-free rate for a period that approximates the expected term of the awards and the expected dividend yield. Income Taxes Apexigen accounts for income taxes under the asset and liability method. Under this method, Apexigen recognizes deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Apexigen measures deferred tax assets and liabilities using enacted tax rates applied to taxable income in the years in which Apexigen expects to realize those temporary differences. Apexigen recognizes the effect on deferred tax assets and liabilities of a change in tax rates as income or loss in the period that includes the enactment date. Apexigen establishes a valuation allowance, when necessary, to reduce deferred tax assets to the amount we expect to realize. Apexigen recognizes financial statement effects of uncertain tax positions when it is more-likely-than-not, Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ deficit that are excluded from net loss, primarily unrealized gains or losses on Apexigen’s marketable securities. Net Loss per Share Apexigen calculates basic net loss per share by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented, since the effects of potentially dilutive securities are antidilutive given Apexigen’s net loss. Recently Adopted Accounting Pronouncements In February 2016, the FASB established Topic 842, Leases No. 2016-02, on-balance No. 2018-10, Codification Improvements to Topic 842, Leases No. 2018-11, Targeted Improvements right-of-use Apexigen early adopted the new standard on January 1, 2020 using the modified retrospective transition method. Apexigen adopted Topic 842 and related ASUs on January 1, 2020. Apexigen elected the package of practical expedients permitted under the transition guidance within Topic 842, which allowed Apexigen to carry forward the historical lease classification, retain the initial direct costs for any leases that existed prior to the adoption of the standard and not reassess whether any contracts entered into prior to the adoption are leases, Upon adoption on January 1, 2020, Apexigen recognized a lease liability of approximately $1.7 million and a right-of-use In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes tax-related Recent Accounting Pronouncements The adoption dates discussed below reflect the election as an emerging growth company. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments off-balance held-to-maturity available-for-sale In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) 815-40), In October 2020, the FASB issued ASU No. 2020-10, Codification Improvements

Fair Value Measurement

Fair Value Measurement	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurement	3. Fair Value Measurement Apexigen records financial assets and liabilities at fair value. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value and expands disclosures about fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. Apexigen categorizes assets and liabilities recorded at fair value in the financial statements based upon the level of judgment associated with the inputs used to measure their fair value. Hierarchical levels are directly related to the amount of subjectivity with the inputs to the valuation of these assets or liabilities as follows: Level 1 Level 2 Level 3 As of June 30, 2022, Apexigen’s cash equivalents consist of money market funds less than a three-month maturity. Its short-term investments consisting of U.S. treasury securities and government debt securities are also recorded as available-for-sale In certain cases where there is limited activity or less transparency around the inputs to valuation, Apexigen classifies securities as Level 3. Level 3 liabilities consist of the preferred stock warrant liability. The following tables set forth Apexigen’s financial instruments that Apexigen measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):​​​​​​​ December 31, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 18,526 $ — $ — $ 18,526 Commercial paper — 5,498 — 5,498 Corporate debt securities — 4,512 — 4,512 Government debt securities — 1,503 — 1,503 Asset backed securities — 1,404 — 1,404 Total $ 18,526 $ 12,917 $ — $ 31,443 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2 June 30, 2022 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 10,538 $ — $ — $ 10,538 U.S. treasury securities 5,991 — — 5,991 Government debt securities — 3,990 — 3,990 Total $ 16,529 $ 3,990 $ — $ 20,519 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2 The only financial liability measured at fair value on a recurring basis is the preferred stock warrant liability, a level 3 instrument, with a fair value of $2,000 as of December 31, 2021 and June 30, 2022. Apexigen estimates the fair value of the preferred stock warrant liability using the Black-Scholes option-pricing model, which requires inputs such as the expected volatility based on comparable public companies, the estimated fair value of the preferred stock, and the estimated time to liquidity. The following tables summarize the estimated fair value of Apexigen’s marketable securities and the gross unrealized holding gains and losses (in thousands): December 31, 2021 Amortized Cost Unrealized Estimated Gains Losses Cash and cash equivalents: Cash $ 4,917 $ — $ — $ 4,917 Money market funds 18,526 — — 18,526 Total cash and cash equivalents $ 23,443 $ — $ — $ 23,443 Marketable securities: Commercial paper $ 5,498 $ — $ — $ 5,498 Corporate debt securities 4,515 — (3 ) 4,512 Government debt securities 1,503 — — 1,503 Asset backed securities 1,405 — (1 ) 1,404 Total marketable securities $ 12,921 $ — $ (4 ) $ 12,917 June 30, 2022 Amortized Cost Unrealized Estimated Fair Value Gains Losses Cash and cash equivalents: Cash $ 1,106 $ — $ — $ 1,106 Money market funds 10,538 — — 10,538 Total cash and cash equivalents $ 11,644 $ — $ — $ 11,644 Marketable securities: U.S. treasury securities $ 5,995 $ — $ (4 ) $ 5,991 Government debt securities 4,003 — (13 ) 3,990 Total marketable securities $ 9,998 $ — $ (17 ) $ 9,981	3. Fair Value Measurement Apexigen records financial assets and liabilities at fair value. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value and expands disclosures about fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. Apexigen categorizes assets and liabilities recorded at fair value in the financial statements based upon the level of judgment associated with the inputs used to measure their fair value. Hierarchical levels are directly related to the amount of subjectivity with the inputs to the valuation of these assets or liabilities as follows: Level 1 Level 2 Level 3 Apexigen’s cash equivalents consisting of money market funds and U.S. treasury securities are classified as Level 1 because they are valued using quoted market prices. Apexigen’s short-term investments, consisting of government debt securities, corporate debt securities, commercial paper, and asset backed securities, recorded as available-for-sale In certain cases where there is limited activity or less transparency around the inputs to valuation, Apexigen classifies securities as Level 3. Level 3 liabilities consist of the preferred stock warrant liability. The following tables set forth Apexigen’s financial instruments that Apexigen measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): December 31, 2020 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 18,201 $ — $ — $ 18,201 U.S. treasury securities 2,500 — — 2,500 Commercial paper — 21,881 — 21,881 Corporate debt securities — 7,494 — 7,494 Asset backed securities — 3,307 — 3,307 Total $ 20,701 $ 32,682 $ — $ 53,383 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2 December 31, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 18,526 $ — $ — $ 18,526 Commercial paper — 5,498 — 5,498 Corporate debt securities — 4,512 — 4,512 Government debt securities — 1,503 — 1,503 Asset backed securities — 1,404 — 1,404 Total $ 18,526 $ 12,917 $ — $ 31,443 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2 The only financial liability measured at fair value on a recurring basis is the preferred stock warrant liability, a level 3 instrument, with a fair value of $2,000 as of December 31, 2020 and 2021. Apexigen estimates the fair value of the preferred stock warrant liability using the Black-Scholes option-pricing model, which requires inputs such as the expected volatility based on comparable public companies, the estimated fair value of the preferred stock, and the estimated time to liquidity. The following tables summarize the estimated fair value of Apexigen’s marketable securities and the gross unrealized holding gains and losses (in thousands): December 31, 2020 Amortized Unrealized Estimated Gains Losses Cash and cash equivalents: Cash $ 7,083 $ — $ — $ 7,083 Money market funds 18,201 — — 18,201 Total cash and cash equivalents $ 25,284 $ — $ — $ 25,284 Marketable securities: U.S. treasury securities $ 2,499 $ 1 $ — $ 2,500 Commercial paper 21,881 — — 21,881 Corporate debt securities 7,492 2 — 7,494 Asset backed securities 3,307 — — 3,307 Total marketable securities $ 35,179 $ 3 $ — $ 35,182 December 31, 2021 Amortized Unrealized Estimated Gains Losses Cash and cash equivalents: Cash $ 4,917 $ — $ — $ 4,917 Money market funds 18,526 — — 18,526 Total cash and cash equivalents $ 23,443 $ — $ — $ 23,443 Marketable securities: Commercial paper $ 5,498 $ — $ — $ 5,498 Corporate debt securities 4,515 — (3 ) 4,512 Government debt securities 1,503 — — 1,503 Asset backed securities 1,405 — (1 ) 1,404 Total marketable securities $ 12,921 $ — $ (4 ) $ 12,917

Balance Sheet Components

Balance Sheet Components	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Balance Sheet Components [Abstract]
Balance Sheet Components	4. Balance Sheet Components Property and Equipment, Net Property and equipment, net consists of the following (in thousands): December 31, 2021 June 30, 2022 Laboratory equipment $ 943 $ 894 Furniture and fixtures 28 28 Office equipment 25 25 Software 12 12 Total property and equipment 1,008 959 Less: accumulated depreciation (763 ) (769 ) Total property and equipment, net $ 245 $ 190 Depreciation expense for property and equipment was $26,000 and $28,000 for the three months ended June 30, 2021 and 2022, respectively, and $53,000 and $55,000 for the six months ended June 30, 2021 and 2022, respectively. Accrued Liabilities Accrued liabilities consist of the following (in thousands): December 31, 2021 June 30, 2022 Accrued clinical trial and manufacturing costs $ 6,472 $ 5,667 Accrued personnel costs 1,172 1,034 Other accrued liabilities 844 796 Total accrued liabilities $ 8,488 $ 7,497	4. Balance Sheet Components Property and Equipment, Net Property and equipment, net consists of the following (in thousands): December 31, 2020 2021 Laboratory equipment $ 909 $ 943 Furniture and fixtures 28 28 Office equipment 30 25 Software 12 12 Total property and equipment 979 1,008 Less: accumulated depreciation (670 ) (763 ) Total property and equipment, net $ 309 $ 245 Depreciation expense for property and equipment was $127,000 and $105,000 for the years ended December 31, 2020 and 2021, respectively. Accrued Liabilities Accrued liabilities consist of the following (in thousands): December 31, 2020 2021 Accrued clinical trial and manufacturing costs $ 4,818 $ 6,472 Accrued personnel costs 1,142 1,172 Other accrued liabilities 637 844 Total accrued liabilities $ 6,597 $ 8,488

Leases

Leases	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Leases [Abstract]
Leases	5. Leases Apexigen leases its principal facility under a non-cancelable right-of-use Future minimum lease payments as of June 30, 2022, are as follows (in thousands): Operating Leases Year ending December 31, 2022 (6 months remaining) $ 212 2023 106 Total undiscounted future lease payments 318 Less: imputed interest (6 ) Total lease liabilities $ 312	5. Leases Apexigen recognizes lease liabilities based on the present value of the remaining minimum rental payments under current leasing standards for existing operating leases. The right-of-use right-of-use Apexigen leases its principal facility under a non-cancelable one-year Future minimum lease payments as of December 31, 2021, are as follows (in thousands): Year ending December 31, Operating Leases 2022 $ 422 2023 106 Total undiscounted future lease payments 528 Less: imputed interest (18 ) Total lease liabilities $ 510

Convertible Preferred Stock

Convertible Preferred Stock	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Equity [Abstract]
Convertible Preferred Stock	6. Convertible Preferred Stock Apexigen’s authorized, issued and outstanding shares, carrying value and aggregate liquidation preferences of its convertible preferred stock at December 31, 2021 and June 30, 2022 are as follows (in thousands, except for share amounts): Convertible Preferred Stock Shares Authorized Shares Issued and Carrying Value Liquidation Preference Series A-1 39,196,116 39,196,116 $ 19,787 $ 19,990 Series A-2 12,652,762 12,625,343 2,525 2,525 Series B 14,218,546 14,218,546 14,895 15,000 Series C 82,503,347 79,090,623 121,500 122,570 Total 148,570,771 145,130,628 $ 158,707 $ 160,085 The characteristics of the convertible preferred stock are as follows: Dividend Provisions In each calendar year, the holders of each share of then-outstanding preferred stock shall be entitled to receive, when and if declared by the Board, out of any funds and assets of Apexigen legally available therefore, noncumulative dividends at the annual rate of $0.0408 per share for Series A-1, A-2, no Conversion Rights Each share of preferred stock is convertible, at the option of the holder of preferred stock, into the number of shares of common stock that results from dividing the original issue price for such series of preferred stock by the conversion price for such series of preferred stock that is in effect at the time of conversion. The initial conversion price for each series of preferred stock is the original issue price for such series of preferred stock. The conversion price of each series of preferred stock may be subject to adjustment from time to time from stock splits, combinations, reorganizations, reclassifications, consolidations, or sales of shares below the applicable conversion price. All of the preferred stock will automatically convert into fully paid and non-assessable Apexigen pursuant to an effective registration statement filed under the Securities Act of 1933, as amended, covering the offer and sale of common stock provided that the aggregate gross proceeds to Apexigen are not less than $30.0 million or in the event that holders of at least 50% of the outstanding shares of Series A-1, as-converted Voting Rights Each holder of shares of outstanding preferred stock is entitled to cast the number of votes equal to the number of whole shares of common stock into which such shares of preferred stock may convert. Liquidation Preference In the event of any voluntary or involuntary liquidation, dissolution or winding up of Apexigen, or deemed liquidation event, the funds and assets that may be legally distributed to Apexigen’s stockholders will be distributed to the holders of Series C preferred stock in preference to the holders of Series B, Series A-1, A-2 A-1, A-2 A-1 A-2 A-1, A-2 as-converted	6. Convertible Preferred Stock In 2020, Apexigen issued an aggregate of 8,602,082 shares of Series C preferred stock in exchange for gross proceeds of approximately $13.3 million. Apexigen’s authorized, issued and outstanding shares, carrying value and aggregate liquidation preferences of its convertible preferred stock at December 31, 2020 and 2021 are as follows (in thousands, except for share amounts): Convertible Preferred Stock Shares Shares Carrying Value Liquidation Series A-1 39,196,116 39,196,116 $ 19,787 $ 19,990 Series A-2 12,652,762 12,625,343 2,525 2,525 Series B 14,218,546 14,218,546 14,895 15,000 Series C 82,503,347 79,090,623 121,500 122,570 Total 148,570,771 145,130,628 $ 158,707 $ 160,085 At December 31, 2020 and 2021, the characteristics of the convertible preferred stock are as follows: Dividend Provisions In each calendar year, the holders of each share of then-outstanding preferred stock shall be entitled to receive, when and if declared by the Board, out of any funds and assets of Apexigen legally available therefore, noncumulative dividends at the annual rate of $0.0408 per share for Series A-1, A-2, Conversion Rights Each share of preferred stock is convertible, at the option of the holder of preferred stock, into the number of shares of common stock that results from dividing the original issue price for such series of preferred stock by the conversion price for such series of preferred stock that is in effect at the time of conversion. The initial conversion price for each series of preferred stock is the original issue price for such series of preferred stock. The conversion price of each series of preferred stock may be subject to adjustment from time to time from stock splits, combinations, reorganizations, reclassifications, consolidations, or sales of shares below the applicable conversion price. All of the preferred stock will automatically be converted into fully paid and non-assessable A-1, as-converted Voting Rights Each holder of shares of outstanding preferred stock is entitled to cast the number of votes equal to the number of whole shares of common stock into which such shares of preferred stock could be converted. Liquidation Preference In the event of any voluntary or involuntary liquidation, dissolution or winding up of Apexigen, or deemed liquidation event, the funds and assets that may be legally distributed to Apexigen’s stockholders will be distributed to the holders of Series C preferred stock in preference to the holders of Series B, Series A-1, Series A-2 A-1, A-2 A-1 A-2 A-1, A-2 as-converted

Common Stock

Common Stock	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Common Stock	7. Common Stock The holders of common stock are entitled to one vote per share on all matters to be voted on by the stockholders of Apexigen. Subject to the preferences that may be applicable to any outstanding shares of the convertible preferred stock, the holders of the common stock are entitled to receive ratably such dividends, if any, as the Board may declare. The Board has declared no dividends to date. At June 30, 2022, Apexigen has reserved the following shares of common stock for the following purposes: Series A-1 39,196,116 Series A-2 12,625,343 Series B convertible preferred stock outstanding, as converted 14,218,546 Series C convertible preferred stock outstanding, as converted 79,090,623 Options issued and outstanding 33,755,492 Options available for future grants 9,048,183 Common stock warrants 102,998 Series A-2 27,419 Total common stock reserved for issuance 188,064,720	7. Common Stock The holders of common stock are entitled to one vote per share on all matters to be voted on by the stockholders of Apexigen. Subject to the preferences that may be applicable to any outstanding shares of the convertible preferred stock, the holders of the common stock are entitled to receive ratably such dividends, if any, as the Board may declare. The Board has declared no dividends to date. At December 31, 2021, Apexigen has reserved the following shares of common stock for the following purposes: Series A-1 39,196,116 Series A-2 12,625,343 Series B convertible preferred stock outstanding, as converted 14,218,546 Series C convertible preferred stock outstanding, as converted 79,090,623 Options issued and outstanding 34,522,687 Options available for future grants 8,671,812 Common stock warrants 102,998 Series A-2 27,419 Total common stock reserved for issuance 188,455,544

Clinical Study Agreement Amendm

Clinical Study Agreement Amendment With Parker Institute	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Clinical Study Agreement Amendment with Parker Institute [Abstract]
Clinical Study Agreement Amendment with Parker Institute	8. Clinical Study Agreement Amendment with Parker Institute In April 2017, Apexigen entered into a collaboration agreement with Parker Institute for Cancer Immunotherapy (“PICI”) for the clinical development of sotiga. Under the terms of the arrangement, PICI funded the cost of a clinical trial of sotiga in combination with other agents in pancreatic cancer, and Apexigen supplied sotiga and provided related services. In October 2019, Apexigen and PICI amended the agreement to update Apexigen’s payment obligations. As a result of the amendment, Apexigen paid $1.0 million and issued 1,290,540 shares of its common stock to PICI as compensation for services previously rendered. The $1.0 million payment and the fair value of the common stock of $0.9 million were recognized immediately as research and development expense. Upon PICI’s completion of milestones in 2020, Apexigen recognized $0.7 million in research and development expenses. There were no expenses recognized during the three and six months ended June 30, 2021 and 2022. Future amounts of up to an aggregate of $9.5 million in cash and shares of Apexigen’s common stock are payable based on the achievement of certain clinical development milestones, none of which were probable as of June 30, 2022, and no amounts have been recognized.	8. Clinical Study Agreement Amendment with Parker Institute In April 2017, Apexigen entered into a collaboration agreement with Parker Institute for Cancer Immunotherapy (“PICI”) for the clinical development of sotiga. Under the terms of the arrangement, PICI funded the cost of a clinical trial of sotiga in combination with other agents in pancreatic cancer, and Apexigen supplied sotiga and provided related services at no cost. Upon achievement of certain clinical development and regulatory milestones by APX005M in pancreatic cancer, Apexigen will be obligated to pay back a multiple of PICI’s trial costs. In October 2019, Apexigen and PICI amended the agreement to update Apexigen’s payment obligations. As a result of the amendment, Apexigen paid $1.0 million in cash and issued 1,290,540 shares of its common stock to PICI as compensation for services previously rendered. The cash payment and the fair value of the common stock of $0.9 million were recognized immediately as research and development expense. Upon the completion of the other milestones, Apexigen recognized $0.7 million in research and development expenses for the year ended December 31, 2020. There were no expenses recognized during the year ended December 31, 2021. Future amounts of up to an aggregate of $9.6 million in cash and shares of Apexigen’s common stock are payable based on the achievement of certain clinical development milestones, none of which were probable as of December 31, 2021, and no amounts have been recognized.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation In December 2010, Apexigen adopted the 2010 Stock Incentive Plan and 2010 Equity Incentive Plan, which expired in 2020. In August 2020, Apexigen adopted the 2020 Equity Incentive Plan (the 2020 Plan and, together with the 2010 Stock Incentive Plan and the 2010 Equity Incentive Plan, the “Plans”). As of June 30, 2022, Apexigen had reserved 42,803,675 shares of common stock for the issuance of incentive and nonstatutory stock options to purchase common stock, stock awards, and restricted stock awards to employees, directors, and consultants under the Plans. The Board determines the period over which options become exercisable and options generally vest over a four-year period. No option will become exercisable after the expiration of ten years from the date of grant. The term of an incentive stock option (“ISO”) granted to a 10% stockholder will not exceed five years from the date of the grant. The exercise price of an ISO and nonstatutory stock option (“NSO”) will not be less than 100% of the estimated fair value of the shares on the date of grant, respectively, and the exercise price of an ISO and NSO granted to a 10% stockholder will not be less than 110% of the estimated fair value of the shares on the date of grant. In February 2021, Apexigen entered into a consulting agreement with a board member and granted an option (the “Stock Option”) to acquire 200,000 shares of common stock. The Stock Option vests upon the achievement of certain performance milestones and has a ten-year Stock Compensation option Stock-based compensation is included in the statements of operations and comprehensive loss in research and development and general and administrative expense depending on the nature of the services provided. The following table illustrates stock-based compensation expense related to stock options granted under the Plans recognized for three and six months ended June 31, 2021 and 2022 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2022 2021 2022 Research and development $ 54 $ 139 $ 186 $ 258 General and administrative 208 229 436 531 Total stock-based compensation $ 262 $ 368 $ 622 $ 789 During the six months ended June 30, 2021 and 2022, Apexigen granted options to purchase 1,545,000 shares and 5,397,344 shares with a weighted-average exercise price of $0.47 and $0.51 per share, respectively. For the options granted during the six months ended June 30, 2021 and 2022, Apexigen expects to recognize $0.5 million and $1.9 million of stock-based compensation over the related vesting period, respectively. The weighted-average grant date fair value of options granted during the six months ended June 30, 2021 and 2022 was $0.35 and $0.36 per share, respectively. During the six months ended June 30, 2021 and 2022, Apexigen cancelled options to purchase 1,737,530 shares and 5,773,715 shares, respectively. For the six months ended June 30, 2021 and 2022, the aggregate intrinsic value of the options exercised was $0.2 million. At June 30, 2022, there was $2.6 million of unrecognized stock-based compensation cost related to stock options granted to employees and others under the Plans, which Apexigen expects to recognize over a weighted average period of 2.7 years.	9. Stock-Based Compensation In December 2010, Apexigen adopted the 2010 Stock Incentive Plan and 2010 Equity Incentive Plan, which expired in 2020. In August 2020, Apexigen adopted the 2020 Equity Incentive Plan (the 2020 Plan and, together with the 2010 Stock Incentive Plan and the 2010 Equity Incentive Plan, the Plans). As of December 31, 2021, Apexigen had reserved 43,194,499 shares of common stock for the issuance of incentive and nonstatutory stock options to purchase common stock, stock awards, and restricted stock awards to employees, directors, and consultants under the Plans. The Board determines the period over which options become exercisable and options generally vest over a four-year period. No option will become exercisable after the expiration of ten years from the date of grant. The term of an incentive stock option (“ISO”) granted to a 10% stockholder will not exceed five years from the date of the grant. The exercise price of an ISO and nonstatutory stock option (“NSO”) will not be less than 100% of the estimated fair value of the shares on the date of grant, respectively, and the exercise price of an ISO and NSO granted to a 10% stockholder will not be less than 110% of the estimated fair value of the shares on the date of grant. On August 6, 2020, the Board approved the repricing of 4,438,847 stock options for various employees using a new exercise price of $0.47 per share, which represented the estimated fair value of a share of Apexigen’s common stock on the repricing date. The weighted-average grant date fair value of options repriced was $0.31 per share. The stock options originally had a range of exercise prices from $0.67 to $0.74 per share. The repriced stock options will continue to vest according to their original vesting schedules and will retain their original expiration dates. Apexigen compared the fair value of the modified options and the fair value of the original options immediately before and after the terms and conditions were modified. Since the fair value of the modified awards exceeds the fair value of the original awards at the modification date, the repricing resulted in incremental compensation cost of $156,000, of which $26,000 was immediately recognized as stock-based compensation for the vested repriced options at the modification date. After the modification date, Apexigen recognized $28,000 as stock-based compensation for the remainder of the year ended December 31, 2020. During the year ended December 31, 2021, Apexigen recognized $31,000 of stock-based compensation. At December 31, 2021, there was $40,000 of unrecognized incremental compensation cost, which is expected to be recognized over a weighted average period of 1.8 years. In February 2021, Apexigen entered into a consulting agreement with a board member and granted an option (the “Stock Option”) to acquire 200,000 shares of common stock. The Stock Option vests upon the achievement of certain performance milestones and has a ten-year Stock Compensation Stock-based compensation is included in the statements of operations and comprehensive loss in research and development and general and administrative expense depending on the nature of the services provided. The following table illustrates stock-based compensation expense related to stock options granted under the Plans recognized for the years indicated (in thousands): Years Ended 2020 2021 Research and development $ 531 $ 292 General and administrative 814 851 Total stock-based compensation $ 1,345 $ 1,143 The grant date fair value of the shares of common stock underlying stock options was determined by the Board with the assistance of management and an independent third-party valuation specialist. Because there was no public market for Apexigen’s common stock, the Board determined fair value of the common stock at the time of grant of the option by considering a number of objective and subjective factors including important developments in Apexigen’s operations, valuations performed by an independent third party, sales of convertible preferred stock, actual operating results and financial performance, the conditions in the biotechnology industry and the economy in general, the stock price performance and volatility of comparable public companies, and the lack of liquidity of Apexigen’s common stock, among other factors. In determining the fair value of the options granted, Apexigen used the Black-Scholes option-pricing model and the following assumptions: Years Ended December 31, 2020 2021 Expected term (years) 5.00 - 10.00 5.62 - 10.00 Expected volatility 75% to 82% 88% Risk-free interest rate 0.27% - 1.51% 0.60% - 1.20% Expected dividend 0% 0% In determining the fair value of the repriced options and the original options at the modification date, Apexigen used the Black-Scholes option-pricing model and the following assumptions: Reprice Expected term (years) 4.26 - 6.47 Expected volatility 80% Risk-free interest rate 0.18% - 0.34% Expected dividend 0% The assumptions used to determine the fair value of the stock options are as follows: • Expected volatility: Because Apexigen’s stock is not traded in an active market, Apexigen calculates volatility by using the historical volatilities of the common stock of comparable publicly traded companies. The historical volatility data was computed using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of the stock-based awards. Apexigen will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. • Risk-free interest rate: Apexigen bases the risk-free interest rate from the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. • Expected term: Apexigen determines the expected life of options granted using the “simplified” method. Under this approach, Apexigen presumes the expected term to be the mid-point weighted-average vesting term and the contractual term of the option. The simplified method makes the assumption that the award recipient will exercise share options evenly over the period when the share options are vested and ending on the date when the share options would expire. • Expected dividend yield: Apexigen has never paid cash dividends on its common stock and does not have plans to pay cash dividends in the future. Therefore, Apexigen uses an expected dividend yield of zero. • Common Stock Valuation: Given the absence of a public trading market of Apexigen’s common stock, the Board considers numerous subjective and objective factors to determine the best estimate of fair value of Apexigen’s common stock underlying the stock options granted to its employees and non-employees. The following table summarizes stock option activity under the Plans (in thousands, except share and per share amounts): Options Number of Weighted Weighted Aggregate Outstanding at December 31, 2020 8,371,662 35,371,809 $ 0.27 Granted (1,545,000 ) 1,545,000 $ 0.47 Exercised — (548,972 ) $ 0.18 Cancelled 1,845,150 (1,845,150 ) $ 0.39 Outstanding at December 31, 2021 8,671,812 34,522,687 $ 0.28 5.07 $ 7,095 Vested and exercisable at December 31, 2021 30,442,623 $ 0.25 4.63 $ 7,052 Vested and expected to vest at December 31, 2021 34,372,687 $ 0.28 5.05 $ 7,095 The weighted-average grant date fair value of options granted during the years ended December 31, 2020 and 2021 was $0.44 per share and $0.35 per share, respectively. At December 31, 2021, there was $1.5 million of unrecognized stock-based compensation cost related to stock options granted to employees and others under the Plans, which Apexigen expects to recognize over a weighted average period of 1.9 years. During the year ended December 31, 2020, the aggregate intrinsic value of the options exercised was not significant. For the year ended December 31, 2021, the aggregate intrinsic value of the options exercised was $0.2 million.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Indemnification Apexigen has agreed to indemnify the officers and board of directors with respect to the Transaction (see Note 1). Apexigen has agreed to hold them harmless against losses arising from liability claims made by third parties related to the Transaction. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. It is not possible to determine the maximum potential amount under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. Since these agreements were effective after June 30, 2022, there were no payments made by Apexigen under these agreements as of June 30, 2022. As of June 30, 2022, there was no Other No liabilities for loss contingencies arising from claims, assessments, litigation, fines, and penalties and other sources are recorded as it is not probable that a liability has been incurred and the amount can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred. Apexigen enters into contracts in the normal course of business with contract research organizations for preclinical studies and clinical trials and contract manufacturing organizations for the manufacture of clinical trial materials.	10. Commitments and Contingencies License Agreement In September 2010, Apexigen entered into an exclusive license agreement with Epitomics for the use of certain Epitomics patents and know-how the extent such amounts are received in consideration of the grant of a sublicense under the Abcam patents. Under the agreement with Novartis (see Note 2), Apexigen had received royalty proceeds totaled $1.9 million and $3.6 million as of December 31, 2020 and 2021, respectively, of which Apexigen is required to pay a percentage to Abcam. In July 2021, Apexigen and Abcam reached agreements to extend the time for Apexigen to pay Abcam its portion of the royalty proceeds to July 2022. There was $0.2 million and $0.4 million contingently due under this license agreement as of December 31, 2020 and 2021. As of December 31, 2020 and 2021, Apexigen has neither paid nor recorded any portion of this $0.4 million contingent liability to Abcam. Other No liabilities for loss contingencies arising from claims, assessments, litigation, fines, and penalties and other sources are recorded as it is not probable that a liability has been incurred and the amount can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred. Apexigen enters into contracts in the normal course of business with contract research organizations for preclinical studies and clinical trials and contract manufacturing organizations for the manufacture of clinical trial materials.

Income Taxes

Income Taxes	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The effective tax rate for the three months ended June 30, 2021 and 2022 was zero. The difference between the effective income tax rate and the U.S. federal statutory rate of 21% is primarily attributable to recording valuation allowances to offset deferred tax assets arising from federal and state net operating losses.	11. Income Taxes Apexigen recorded no provision for income taxes for the years ended December 31, 2020 and 2021. Apexigen incurred net operating losses for all the periods presented. The effective tax rate of the provision for income taxes differs from the federal statutory rate as follows: Years Ended 2020 2021 Federal statutory income tax rate 21.0 % 21.0 % Permanent differences (0.5 )% (0.3 )% Other credit 1.7 % 3.2 % Other 0.6 % (0.3 )% State rate change impact (21.0 )% 0.0 % Change in valuation allowance (1.8 )% (23.6 )% 0.0 % 0.0 % The components of the deferred tax assets and liabilities are as follows (in thousands): Years Ended 2020 2021 Deferred tax assets: Net operating loss carry forwards $ 21,135 $ 27,217 Tax credits 3,049 3,964 Other reserves and accruals 1,641 1,334 Gross deferred tax assets 25,825 32,515 Deferred tax liabilities: Depreciation and amortization (32 ) (24 ) Right-of-use (236 ) (101 ) Gross deferred tax liabilities (268 ) (125 ) Valuation allowance (25,557 ) (32,390 ) Net deferred tax assets $ — $ — Realization of the deferred tax assets depends upon future taxable income. Since the amount and timing of future income are uncertain, the net deferred tax assets as of December 31, 2020 and 2021 have been fully offset by a valuation allowance. The valuation allowance increased by $0.4 million and $6.8 million during the years ended December 31, 2020 and 2021, respectively. As of December 31, 2021, Apexigen had federal net operating loss (“NOL”) carryforwards totaling $129.6 million. Of the $129.6 million, $101.4 million related to NOLs generated after December 31, 2017 and are carried forward indefinitely but are subject to an 80% of taxable income limitation, and $28.3 million will begin to expire in 2033. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) permits NOL carryovers and carrybacks to offset 100% of taxable income for years beginning before 2021. In addition, the CARES Act allows NOLs incurred in 2018, 2019 and 2020 to be carried back to each of the five preceding taxable years. The CARES Act did not have an impact to Apexigen’s NOLs. As of December 31, 2021, Apexigen had state NOL carryforward of $64.5 million, which will begin to expire in 2035. Apexigen also has federal and state research and development tax credits of $3.1 million and $2.3 million, respectively, as of December 31, 2021. The federal research credits will begin to expire in the year 2030, and the state research credits have no expiration date. Apexigen qualified for Federal Orphan Drug credit in 2020 and started to claim the credit for tax year 2021. As of December 31, 2021, Apexigen has federal Orphan Drug credits of $0.5 million, which will begin to expire in 2041. Apexigen’s NOL and credit carryforwards may be subject to annual limitations due to ownership change provisions by the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitation may result in the expiration of NOLs and tax credits before utilization. Apexigen elected to recognize, if incurred, interest and penalties related to liabilities for uncertain tax positions as a part of income tax expense. Apexigen has incurred no such interest and penalties to date. Apexigen determines its uncertain tax positions based on whether and how much of a tax benefit taken by Apexigen in its tax filings is more likely than not to be sustained upon examination by the relevant income tax authorities. A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands): Years Ended 2020 2021 Gross unrecognized tax benefit at January 1 $ 966 $ 1,181 Additions for tax provision taken in the current year 215 417 Gross unrecognized tax benefit at December 31 $ 1,181 $ 1,598 Apexigen does not expect the unrecognized tax benefits to change significantly over the next 12 months. Apexigen files income tax returns in the U.S. federal jurisdiction and the states of California and New York. Apexigen is subject to examination by the Internal Revenue Service and the state jurisdictions for all tax years.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	12. Net Loss Per Share The following outstanding potentially dilutive common stock equivalents have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:​​​​​​​ As of June 30, 2021 2022 Series A-1 39,196,116 39,196,116 Series A-2 12,625,343 12,625,343 Series B convertible preferred stock 14,218,546 14,218,546 Series C convertible preferred stock 79,090,623 79,090,623 Stock options 34,790,307 33,755,492 Common stock warrants 102,998 102,998 Series A-2 27,419 27,419 Total common stock reserved for issuance 180,051,352 179,016,537

401(k) Plan

401(k) Plan	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
401(k) Plan	12. 401(k) Plan Apexigen has a 401(k) retirement plan that covers all employees. The 401(k) plan provides for voluntary contributions by employees of up to 100% of their eligible compensation, subject to the maximum allowed by law. Apexigen matches employee contributions up to a maximum of 4% of their salary. Apexigen recognized related expense of $128,000 and $139,000 for the years ended December 31, 2020 and 2021, respectively.

Subsequent Events

Subsequent Events	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Event The Company has evaluated subsequent events through August 18, 2022, and determined that there have been no events that have occurred that would require adjustments to the disclosures in the financial statements. The Transaction closed on July 29, 2022. Refer to Note 1 for further detail.	13. Subsequent Events The Company has evaluated subsequent events through April 8, 2022, and determined that there have been no events that have occurred that would require adjustments to the disclosures in the financial statements. On January 23, 2022, Apexigen granted 110,344 shares of On March 17, 2022, Brookline Capital Acquisition Corp. (“BCAC”) and Apexigen entered into a definitive business combination agreement (“Business Combination Agreement”) pursuant to which BCAC and Apexigen would combine, with the former equityholders of both entities holding equity in the combined public company listed on the Nasdaq Stock Exchange (the “Combined Company”) and with Apexigen’s existing equityholders owning a majority of the equity in the combined public company. It is expected that there will be a substantial rollover of equity by the existing equityholders of Apexigen. Under the Business Combination Agreement, the transaction values Apexigen at $205.0 million on a net-equity pre-closing

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Unaudited Interim Financial Statements	Unaudited Interim Financial Statements The condensed balance sheet as of June 30, 2022, the condensed statements of operations and comprehensive loss for the three and six months ended June 30, 2021 and 2022, the condensed statements of convertible preferred stock and stockholders’ deficit for the three and six months ended June 30, 2021 and 2022, and the condensed statements of cash flows for the six months ended June 30, 2021 and 2022 are unaudited. The unaudited condensed financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal, recurring adjustments that are necessary to present fairly Apexigen’s financial position as of June 30, 2022, its results of operations for the three and six months ended June 30, 2021 and 2022 and its cash flows for the six months ended June 30, 2021 and 2022. The financial data and the other financial information contained in these notes to the condensed financial statements related to the three and six month periods are also unaudited. The condensed balance sheet as of December 31, 2021, is derived from Apexigen’s audited financial statements. The results of operations for the three and six months ended June 30, 2022, are not necessarily indicative of the results to be expected for the year ending December 31, 2022, or for any other future annual or interim period. These condensed financial statements are not complete and are to be read in conjunction with Apexigen’s audited financial statements and the related notes for the year ended December 31, 2021.
Basis of Presentation	Basis of Presentation Apexigen prepares the financial statements and accompanying notes in accordance with accounting principles generally accepted in the United States of America (“GAAP”).	Basis of Presentation Apexigen prepares the financial statements and accompanying notes in accordance with accounting principles generally accepted in the United States of America (“GAAP”).
Emerging Growth Company	Emerging Growth Company Apexigen is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), and it may take advantage of certain exemptions from various reporting requirements that are applicable to public companies that are not emerging growth companies. Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that an emerging growth company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging growth	Emerging Growth Company Apexigen is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), and it may take advantage of certain exemptions from various reporting requirements that are applicable to public companies that are not emerging growth companies. Section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act) are required to comply with the new or revised financial accounting standards. The JOBS Act provides that an emerging growth company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging growth
Use of Estimates	Use of Estimates The preparation of 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 financial statements and the reported amounts expensed during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to accruals for research and development costs, stock-based compensation, uncertain tax positions and fair values of common stock and preferred stock. Apexigen adjusts such estimates and assumptions when facts and circumstances dictate. Changes in those estimates resulting from continuing changes in the economic environment will be reflected in the financial statements in future periods. As future events and their effects cannot be determined with precision, actual results could materially differ from those estimates and assumptions.​​​​​​​	Use of Estimates The preparation of 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 financial statements and the reported amounts expensed during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to accruals for research and development costs, stock-based compensation and uncertain tax positions. Actual results could differ from those estimates.
Segment Reporting	Segment Reporting Apexigen has one	Segment Reporting Apexigen has one operating segment, which is the business of researching, developing and commercializing antibody therapeutics for oncology. Apexigen’s chief operating decision maker, its Chief Executive Officer, manages Apexigen’s operations on an aggregated basis for the purposes of allocating resources and evaluating financial performance.
Cash and Cash Equivalents	Cash and Cash Equivalents Apexigen considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market funds and corporate debt securities. The carrying amount of cash equivalents approximates their fair value.	Cash and Cash Equivalents Apexigen considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market funds, commercial paper, U.S. government and corporate securities. The carrying amount of cash equivalents approximates their fair value.
Short-Term Investments	Short-Term Investments Short-term investments consist of debt securities with original maturities of greater than three months from the date of purchase but less than one year from the balance sheet date. Such investments are considered available-for-sale	Short-Term Investments Short-term investments consist of debt securities with original maturities of greater than three months from the date of purchase but less than one year from the balance sheet date. Such investments are considered available-for-sale
Fair Value Measurements	Fair Value Measurements Apexigen applies fair value accounting to all financial assets and liabilities and non-financial	Fair Value Measurements Apexigen applies fair value accounting to all financial assets and liabilities and non-financial
Concentrations of Credit and Other Risks	Concentrations of Credit and Other Risks Financial instruments that potentially subject Apexigen to a concentration of credit risk consist primarily of cash and cash equivalents and short-term investments. Apexigen holds its bank deposits at accredited financial institutions and these deposits may at times exceed insured limits. Apexigen is exposed to credit risk in the event of a default by the financial institutions holding its cash and cash equivalents to the extent of the amounts held in excess of federally insured limits. Apexigen limits its credit risk associated with cash and cash equivalents by placing them with financial institutions it believes are of high quality. Apexigen has not experienced any losses on its deposits of cash. Apexigen’s investment policy limits investments to certain types of securities issued by the U.S. government, its agencies and institutions with investment-grade credit ratings and places restrictions on maturities and concentration by type and issuer. As of June 30, 2021 and 2022, Apexigen had no off-balance Apexigen is subject to a number of risks similar to other early-stage biopharmaceutical companies, including the need to obtain adequate additional funding, possible failure of clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of Apexigen’s products, and protection of proprietary technology. If Apexigen does not successfully develop, obtain regulatory approval for, commercialize or partner its product candidates, it will be unable to generate revenue from product sales or achieve profitability.	Concentrations of Credit and Other Risks Financial instruments that potentially subject Apexigen to a concentration of credit risk consist primarily of cash and cash equivalents and short-term investments. Apexigen holds Apexigen’s bank deposits at accredited financial institutions and these deposits may at times exceed insured limits. Apexigen is exposed to credit risk in the event of a default by the financial institutions holding its cash and cash equivalents to the extent of the amounts held in excess of federally insured limits. Apexigen limits its credit risk associated with cash and cash equivalents by placing them with financial institutions it believes are of high quality. Apexigen has not experienced any losses on its deposits of cash. Apexigen’s investment policy limits investments to certain types of securities issued by the U.S. government, its agencies and institutions with investment-grade credit ratings and places restrictions on maturities and concentration by type and issuer. As of December 31, 2020 and 2021, Apexigen had no off-balance Apexigen is subject to a number of risks similar to other early-stage biopharmaceutical companies, including the need to obtain adequate additional funding, possible failure of clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of Apexigen’s products, and protection of proprietary technology. If Apexigen does not successfully develop, obtain regulatory approval for, commercialize or partner its product candidates, it will be unable to generate revenue from product sales or achieve profitab ili
Property and Equipment, Net	Property and Equipment, Net Property and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets. The estimated useful life of laboratory equipment, furniture and fixtures, office equipment, and software ranges from t w o	Property and Equipment, Net Property and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets. The estimated useful life of laboratory equipment, furniture and fixtures, office equipment, and software ranges from t w o
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Apexigen’s long-lived assets are comprised principally of its property and equipment and right-of-use	Impairment of Long-Lived Assets Apexigen’s long-lived assets are comprised principally of its property and equipment and right-of-use
Deferred Transaction Costs	Deferred Transaction Costs Deferred transaction costs consist of direct legal, accounting, filing and other fees and costs directly attributable to the anticipated Transaction (see Note 1). Apexigen will offset any deferred transaction costs against the proceeds received upon the closing of the Transaction. Apexigen capitalized and included in prepaid expenses and other current assets deferred transaction costs of $0.5 million and $2.3 million on the balance sheets as of December 31, 2021 and June 30, 2022, respectively.
Deferred Offering Costs		Deferred Offering Costs Deferred offering costs consist of direct legal, accounting, filing and other fees and costs directly attributable to an anticipated equity offering. Apexigen will offset any deferred offering costs against the proceeds received upon the closing of the Transaction (see Note 13). Apexigen capitalized and included in prepaid expenses and other current assets deferred offering costs of $0.4 million on the balance sheet as of December 31, 2021.
Revenue Recognition	Revenue Recognition Under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers Apexigen may also earn contingent fees, including milestone payments based on counterparty performance and royalties on sales, from collaborations and other out-license significant risk of reversal. Apexigen will recognize sales-based royalties as revenue when the underlying sales occur. In October 2019, Novartis’ Beovu ®	Revenue Recognition Under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers Apexigen may also earn contingent fees, including milestone payments based on counterparty performance and royalties on sales, from collaborations and other out-license ®
Leases	Leases Apexigen determines if an arrangement is a lease at inception and if so, determines whether the lease qualifies as an operating or a finance lease. Apexigen includes operating leases in operating lease right-of-use Apexigen leases its facilities under non-cancelable non-cancellable	Leases Apexigen determines if an arrangement is a lease at inception and if so, determines whether the lease qualifies as an operating or a finance lease. Apexigen includes operating leases in operating lease right-of-use Apexigen leases its facilities under non-cancelable non-cancellable
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. Research and development expenses are primarily for the development of sotiga, Apexigen’s lead product candidate, as well as APX601 and other product candidates. Research and development costs consist primarily of external costs related to clinical development, contract manufacturing, preclinical development and discovery as well as personnel costs and allocated overhead, such as rent, equipment, depreciation and utilities. Personnel costs consist of salaries, employee benefits and stock-based compensation. Apexigen estimates external research and development expenses based on the services performed, pursuant to contracts with commercial and academic institutions that conduct and manage research and development services on its behalf. Apexigen records the costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued liabilities in the balance sheets. These costs are a component of Apexigen’s research and development expenses. Apexigen accrues for these costs based on factors such as the number of patient visits, the number of active patients, the number of patients enrolled, estimates of the work completed and other measures in accordance with agreements established with its third-party service providers under the service agreements. As actual costs become known, Apexigen adjusts its accrued liabilities. Apexigen has not experienced any significant differences between accrued costs and actual costs incurred. However, the status and timing of actual services performed may vary from Apexigen’s estimates, resulting in adjustments to expense in future periods. Changes in these estimates that result in significant changes to Apexigen’s accruals could significantly affect Apexigen’s results of operations. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized and then expensed as the related goods are delivered or the services are performed. Apexigen evaluates such payments for current or long-term classification based on when they will be realized.	Research and Development Expenses Research and development costs are expensed as incurred. Research and development expenses consist primarily of the development of sotiga, Apexigen’s lead product candidate, as well as APX601 and other product candidates. Research and development costs consist primarily of external costs related to clinical development, contract manufacturing, preclinical development and discovery as well as personnel costs and allocated overhead, such as rent, equipment, depreciation and utilities. Personnel costs consist of salaries, employee benefits and stock-based compensation. Apexigen estimates external research and development expenses based on the services performed, pursuant to contracts with commercial and academic institutions that conduct and manage research and development services on its behalf. Apexigen records the costs of research and development activities based upon the estimated amount of services provided but not yet invoiced and includes these costs in accrued liabilities in the balance sheets. These costs are a component of Apexigen’s research and development expenses. Apexigen accrues for these costs based on factors such as the numbers of subject visits, the number of active patients, the number of patients enrolled, and estimates of the work completed and other measures in accordance with agreements established with its third-party service providers under the service agreements. As actual costs become known, Apexigen adjusts its accrued liabilities. Apexigen has not experienced any significant differences between accrued costs and actual costs incurred. However, the status and timing of actual services performed may vary from Apexigen’s estimates, resulting in adjustments to expense in future periods. Changes in these estimates that result in significant changes to Apexigen’s accruals could significantly affect Apexigen’s results of operations. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized and then expensed as the related goods are delivered or the services are performed. Apexigen evaluates such payments for current or long-term classification based on when they will be realized.
Preferred Stock Warrant Liability	Preferred Stock Warrant Liability Apexigen records at fair value freestanding puttable or redeemable warrants, or warrants which are not considered to be indexed to Apexigen’s stock and includes this amount in accrued expenses on Apexigen’s balance sheets. Apexigen adjusts the carrying value of such warrants to their estimated fair value at the end of each reporting period based upon the value of Apexigen’s convertible preferred stock.	Preferred Stock Warrant Liability Apexigen records at fair value freestanding puttable or redeemable warrants, or warrants which are not considered to be indexed to Apexigen’s stock and includes this amount in accrued expenses on Apexigen’s balance sheets. Apexigen adjusts the carrying value of such warrants to their estimated fair value at the end of each reporting period based upon the value of Apexigen’s convertible preferred stock.
Convertible Preferred Stock	Convertible Preferred Stock Apexigen records convertible preferred stock at its issuance price less issuance costs on the dates of issuance. Upon the occurrence of certain change in control events that are outside Apexigen’s control, including liquidation, sale or transfer of Apexigen, holders of the convertible preferred stock can cause redemption for cash. Apexigen classifies convertible preferred stock outside of stockholders’ deficit on the balance sheets as events triggering the liquidation preferences are not solely within Apexigen’s control. Apexigen adjusts the carrying values of the convertible preferred stock to their liquidation preferences when and if it becomes probable that such an event will occur. No adjustments have been recorded as of December 31, 2021 or June 30, 2022.	Convertible Preferred Stock Apexigen records convertible preferred stock at its issuance price less issuance costs on the dates of issuance. Upon the occurrence of certain change in control events that are outside Apexigen’s control, including liquidation, sale or transfer of Apexigen, holders of the convertible preferred stock can cause redemption for cash. Apexigen classifies convertible preferred stock outside of stockholders’ deficit on the balance sheets as events triggering the liquidation preferences are not solely within Apexigen’s control. Apexigen adjusts the carrying values of the convertible preferred stock to their liquidation preferences when and if it becomes probable that such an event will occur.
Stock-Based Compensation	Stock-Based Compensation Apexigen measures all stock-based awards granted to employees and non-employees Apexigen uses the Black-Scholes option-pricing model to estimate the fair value of stock option awards and recognizes expense using the straight-line attribution approach. The Black-Scholes option-pricing model requires assumptions to be made related to the fair value of Apexigen’s common stock, the expected term of the awards, expected stock priced volatility, risk-free rate for a period that approximates the expected term of the awards and the expected dividend yield.	Stock-Based Compensation Apexigen measures all stock-based awards granted to employees and non-employees Apexigen uses the Black-Scholes option-pricing model to estimate the fair value of stock option awards and recognizes expense using the straight-line attribution approach. The Black-Scholes option-pricing model requires assumptions to be made related to the fair value of Apexigen’s common stock, the expected term of the awards, expected stock priced volatility, risk-free rate for a period that approximates the expected term of the awards and the expected dividend yield.
Income Taxes	Income Taxes Apexigen accounts for income taxes under the asset and liability method. Under this method, Apexigen recognizes deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Apexigen measures deferred tax assets and liabilities using enacted tax rates applied to taxable income in the years in which Apexigen expects to realize those temporary differences. Apexigen recognizes the effect on deferred tax assets and liabilities of a change in tax rates as income or loss in the period that includes the enactment date. Apexigen establishes a valuation allowance, when necessary, to reduce deferred tax assets to the amount we expect to realize. Apexigen recognizes financial statement effects of uncertain tax positions when it is more-likely-than-not,	Income Taxes Apexigen accounts for income taxes under the asset and liability method. Under this method, Apexigen recognizes deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Apexigen measures deferred tax assets and liabilities using enacted tax rates applied to taxable income in the years in which Apexigen expects to realize those temporary differences. Apexigen recognizes the effect on deferred tax assets and liabilities of a change in tax rates as income or loss in the period that includes the enactment date. Apexigen establishes a valuation allowance, when necessary, to reduce deferred tax assets to the amount we expect to realize. Apexigen recognizes financial statement effects of uncertain tax positions when it is more-likely-than-not,
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ deficit that are excluded from net loss, primarily unrealized gains or losses on Apexigen’s marketable securities.	Comprehensive Loss Comprehensive loss includes net loss and certain changes in stockholders’ deficit that are excluded from net loss, primarily unrealized gains or losses on Apexigen’s marketable securities.
Net Loss per Share	Net Loss per Share Apexigen calculates basic net loss per share by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented, since the effects of potentially dilutive securities are antidilutive given Apexigen’s net loss.	Net Loss per Share Apexigen calculates basic net loss per share by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is the same as basic net loss per share for each period presented, since the effects of potentially dilutive securities are antidilutive given Apexigen’s net loss.
Recently Adopted Accounting Pronouncements		Recently Adopted Accounting Pronouncements In February 2016, the FASB established Topic 842, Leases No. 2016-02, on-balance No. 2018-10, Codification Improvements to Topic 842, Leases No. 2018-11, Targeted Improvements right-of-use Apexigen early adopted the new standard on January 1, 2020 using the modified retrospective transition method. Apexigen adopted Topic 842 and related ASUs on January 1, 2020. Apexigen elected the package of practical expedients permitted under the transition guidance within Topic 842, which allowed Apexigen to carry forward the historical lease classification, retain the initial direct costs for any leases that existed prior to the adoption of the standard and not reassess whether any contracts entered into prior to the adoption are leases, Upon adoption on January 1, 2020, Apexigen recognized a lease liability of approximately $1.7 million and a right-of-use In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes tax-related
Recent Accounting Pronouncements	Recent Accounting Pronouncements The adoption dates discussed below reflect the election as an emerging growth company. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments off-balance held-to-maturity available-for-sale	Recent Accounting Pronouncements The adoption dates discussed below reflect the election as an emerging growth company. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments off-balance held-to-maturity available-for-sale In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) 815-40), In October 2020, the FASB issued ASU No. 2020-10, Codification Improvements

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Summary of Apexigen measured at fair value on a recurring basis	The following tables set forth Apexigen’s financial instruments that Apexigen measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):​​​​​​​ December 31, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 18,526 $ — $ — $ 18,526 Commercial paper — 5,498 — 5,498 Corporate debt securities — 4,512 — 4,512 Government debt securities — 1,503 — 1,503 Asset backed securities — 1,404 — 1,404 Total $ 18,526 $ 12,917 $ — $ 31,443 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2 June 30, 2022 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 10,538 $ — $ — $ 10,538 U.S. treasury securities 5,991 — — 5,991 Government debt securities — 3,990 — 3,990 Total $ 16,529 $ 3,990 $ — $ 20,519 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2	The following tables set forth Apexigen’s financial instruments that Apexigen measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): December 31, 2020 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 18,201 $ — $ — $ 18,201 U.S. treasury securities 2,500 — — 2,500 Commercial paper — 21,881 — 21,881 Corporate debt securities — 7,494 — 7,494 Asset backed securities — 3,307 — 3,307 Total $ 20,701 $ 32,682 $ — $ 53,383 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2 December 31, 2021 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 18,526 $ — $ — $ 18,526 Commercial paper — 5,498 — 5,498 Corporate debt securities — 4,512 — 4,512 Government debt securities — 1,503 — 1,503 Asset backed securities — 1,404 — 1,404 Total $ 18,526 $ 12,917 $ — $ 31,443 Financial liability: Preferred stock warrant liability $ — $ — $ 2 $ 2 Total $ — $ — $ 2 $ 2
Summary of fair value of Apexigen's marketable securities and the gross unrealized holding gains and losses	The following tables summarize the estimated fair value of Apexigen’s marketable securities and the gross unrealized holding gains and losses (in thousands): December 31, 2021 Amortized Cost Unrealized Estimated Gains Losses Cash and cash equivalents: Cash $ 4,917 $ — $ — $ 4,917 Money market funds 18,526 — — 18,526 Total cash and cash equivalents $ 23,443 $ — $ — $ 23,443 Marketable securities: Commercial paper $ 5,498 $ — $ — $ 5,498 Corporate debt securities 4,515 — (3 ) 4,512 Government debt securities 1,503 — — 1,503 Asset backed securities 1,405 — (1 ) 1,404 Total marketable securities $ 12,921 $ — $ (4 ) $ 12,917 June 30, 2022 Amortized Cost Unrealized Estimated Fair Value Gains Losses Cash and cash equivalents: Cash $ 1,106 $ — $ — $ 1,106 Money market funds 10,538 — — 10,538 Total cash and cash equivalents $ 11,644 $ — $ — $ 11,644 Marketable securities: U.S. treasury securities $ 5,995 $ — $ (4 ) $ 5,991 Government debt securities 4,003 — (13 ) 3,990 Total marketable securities $ 9,998 $ — $ (17 ) $ 9,981	The following tables summarize the estimated fair value of Apexigen’s marketable securities and the gross unrealized holding gains and losses (in thousands): December 31, 2020 Amortized Unrealized Estimated Gains Losses Cash and cash equivalents: Cash $ 7,083 $ — $ — $ 7,083 Money market funds 18,201 — — 18,201 Total cash and cash equivalents $ 25,284 $ — $ — $ 25,284 Marketable securities: U.S. treasury securities $ 2,499 $ 1 $ — $ 2,500 Commercial paper 21,881 — — 21,881 Corporate debt securities 7,492 2 — 7,494 Asset backed securities 3,307 — — 3,307 Total marketable securities $ 35,179 $ 3 $ — $ 35,182 December 31, 2021 Amortized Unrealized Estimated Gains Losses Cash and cash equivalents: Cash $ 4,917 $ — $ — $ 4,917 Money market funds 18,526 — — 18,526 Total cash and cash equivalents $ 23,443 $ — $ — $ 23,443 Marketable securities: Commercial paper $ 5,498 $ — $ — $ 5,498 Corporate debt securities 4,515 — (3 ) 4,512 Government debt securities 1,503 — — 1,503 Asset backed securities 1,405 — (1 ) 1,404 Total marketable securities $ 12,921 $ — $ (4 ) $ 12,917

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Balance Sheet Components [Abstract]
Summary of Property and Equipment, Net	Property and equipment, net consists of the following (in thousands): December 31, 2021 June 30, 2022 Laboratory equipment $ 943 $ 894 Furniture and fixtures 28 28 Office equipment 25 25 Software 12 12 Total property and equipment 1,008 959 Less: accumulated depreciation (763 ) (769 ) Total property and equipment, net $ 245 $ 190	Property and equipment, net consists of the following (in thousands): December 31, 2020 2021 Laboratory equipment $ 909 $ 943 Furniture and fixtures 28 28 Office equipment 30 25 Software 12 12 Total property and equipment 979 1,008 Less: accumulated depreciation (670 ) (763 ) Total property and equipment, net $ 309 $ 245
Summary of Accrued liabilities	Accrued liabilities consist of the following (in thousands): December 31, 2021 June 30, 2022 Accrued clinical trial and manufacturing costs $ 6,472 $ 5,667 Accrued personnel costs 1,172 1,034 Other accrued liabilities 844 796 Total accrued liabilities $ 8,488 $ 7,497	Accrued liabilities consist of the following (in thousands): December 31, 2020 2021 Accrued clinical trial and manufacturing costs $ 4,818 $ 6,472 Accrued personnel costs 1,142 1,172 Other accrued liabilities 637 844 Total accrued liabilities $ 6,597 $ 8,488

Leases (Tables)

Leases (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Leases [Abstract]
Summary of future minimum lease payments	Future minimum lease payments as of June 30, 2022, are as follows (in thousands): Operating Leases Year ending December 31, 2022 (6 months remaining) $ 212 2023 106 Total undiscounted future lease payments 318 Less: imputed interest (6 ) Total lease liabilities $ 312	Future minimum lease payments as of December 31, 2021, are as follows (in thousands): Year ending December 31, Operating Leases 2022 $ 422 2023 106 Total undiscounted future lease payments 528 Less: imputed interest (18 ) Total lease liabilities $ 510

Convertible Preferred Stock (Ta

Convertible Preferred Stock (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Equity [Abstract]
Schedule of Convertible Preferred Stock	Apexigen’s authorized, issued and outstanding shares, carrying value and aggregate liquidation preferences of its convertible preferred stock at December 31, 2021 and June 30, 2022 are as follows (in thousands, except for share amounts): Convertible Preferred Stock Shares Authorized Shares Issued and Carrying Value Liquidation Preference Series A-1 39,196,116 39,196,116 $ 19,787 $ 19,990 Series A-2 12,652,762 12,625,343 2,525 2,525 Series B 14,218,546 14,218,546 14,895 15,000 Series C 82,503,347 79,090,623 121,500 122,570 Total 148,570,771 145,130,628 $ 158,707 $ 160,085	Apexigen’s authorized, issued and outstanding shares, carrying value and aggregate liquidation preferences of its convertible preferred stock at December 31, 2020 and 2021 are as follows (in thousands, except for share amounts): Convertible Preferred Stock Shares Shares Carrying Value Liquidation Series A-1 39,196,116 39,196,116 $ 19,787 $ 19,990 Series A-2 12,652,762 12,625,343 2,525 2,525 Series B 14,218,546 14,218,546 14,895 15,000 Series C 82,503,347 79,090,623 121,500 122,570 Total 148,570,771 145,130,628 $ 158,707 $ 160,085

Common Stock (Tables)

Common Stock (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Summary of Common stock	At June 30, 2022, Apexigen has reserved the following shares of common stock for the following purposes: Series A-1 39,196,116 Series A-2 12,625,343 Series B convertible preferred stock outstanding, as converted 14,218,546 Series C convertible preferred stock outstanding, as converted 79,090,623 Options issued and outstanding 33,755,492 Options available for future grants 9,048,183 Common stock warrants 102,998 Series A-2 27,419 Total common stock reserved for issuance 188,064,720	At December 31, 2021, Apexigen has reserved the following shares of common stock for the following purposes: Series A-1 39,196,116 Series A-2 12,625,343 Series B convertible preferred stock outstanding, as converted 14,218,546 Series C convertible preferred stock outstanding, as converted 79,090,623 Options issued and outstanding 34,522,687 Options available for future grants 8,671,812 Common stock warrants 102,998 Series A-2 27,419 Total common stock reserved for issuance 188,455,544

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Summary of Stock Based Compensation Expense Related To Stock Options Granted	The following table illustrates stock-based compensation expense related to stock options granted under the Plans recognized for three and six months ended June 31, 2021 and 2022 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2021 2022 2021 2022 Research and development $ 54 $ 139 $ 186 $ 258 General and administrative 208 229 436 531 Total stock-based compensation $ 262 $ 368 $ 622 $ 789	The following table illustrates stock-based compensation expense related to stock options granted under the Plans recognized for the years indicated (in thousands): Years Ended 2020 2021 Research and development $ 531 $ 292 General and administrative 814 851 Total stock-based compensation $ 1,345 $ 1,143
Summary of Share Based Payment Award Stock Options Valuation Assumptions		In determining the fair value of the options granted, Apexigen used the Black-Scholes option-pricing model and the following assumptions: Years Ended December 31, 2020 2021 Expected term (years) 5.00 - 10.00 5.62 - 10.00 Expected volatility 75% to 82% 88% Risk-free interest rate 0.27% - 1.51% 0.60% - 1.20% Expected dividend 0% 0%
Summary of Stock Options Activity Under the Plans		The following table summarizes stock option activity under the Plans (in thousands, except share and per share amounts): Options Number of Weighted Weighted Aggregate Outstanding at December 31, 2020 8,371,662 35,371,809 $ 0.27 Granted (1,545,000 ) 1,545,000 $ 0.47 Exercised — (548,972 ) $ 0.18 Cancelled 1,845,150 (1,845,150 ) $ 0.39 Outstanding at December 31, 2021 8,671,812 34,522,687 $ 0.28 5.07 $ 7,095 Vested and exercisable at December 31, 2021 30,442,623 $ 0.25 4.63 $ 7,052 Vested and expected to vest at December 31, 2021 34,372,687 $ 0.28 5.05 $ 7,095
Repriced Stock Options [Member]
Summary of Share Based Payment Award Stock Options Valuation Assumptions		In determining the fair value of the repriced options and the original options at the modification date, Apexigen used the Black-Scholes option-pricing model and the following assumptions: Reprice Expected term (years) 4.26 - 6.47 Expected volatility 80% Risk-free interest rate 0.18% - 0.34% Expected dividend 0%

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule Of Reconciliation Of Effective Tax Rate Of The Provision For Income Taxes	The effective tax rate of the provision for income taxes differs from the federal statutory rate as follows: Years Ended 2020 2021 Federal statutory income tax rate 21.0 % 21.0 % Permanent differences (0.5 )% (0.3 )% Other credit 1.7 % 3.2 % Other 0.6 % (0.3 )% State rate change impact (21.0 )% 0.0 % Change in valuation allowance (1.8 )% (23.6 )% 0.0 % 0.0 %
Summary of components of the deferred tax assets and liabilities	The components of the deferred tax assets and liabilities are as follows (in thousands): Years Ended 2020 2021 Deferred tax assets: Net operating loss carry forwards $ 21,135 $ 27,217 Tax credits 3,049 3,964 Other reserves and accruals 1,641 1,334 Gross deferred tax assets 25,825 32,515 Deferred tax liabilities: Depreciation and amortization (32 ) (24 ) Right-of-use (236 ) (101 ) Gross deferred tax liabilities (268 ) (125 ) Valuation allowance (25,557 ) (32,390 ) Net deferred tax assets $ — $ —
Summary of Reconciliation Of The Beginning And Ending Amounts Of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands): Years Ended 2020 2021 Gross unrecognized tax benefit at January 1 $ 966 $ 1,181 Additions for tax provision taken in the current year 215 417 Gross unrecognized tax benefit at December 31 $ 1,181 $ 1,598

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Summary of Diluted Net Loss Per Share for the Periods Presented Due To Their Anti-Dilutive Effect	The following outstanding potentially dilutive common stock equivalents have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect: As of June 30, 2021 2022 Series A-1 39,196,116 39,196,116 Series A-2 12,625,343 12,625,343 Series B convertible preferred stock 14,218,546 14,218,546 Series C convertible preferred stock 79,090,623 79,090,623 Stock options 34,790,307 33,755,492 Common stock warrants 102,998 102,998 Series A-2 27,419 27,419 Total common stock reserved for issuance 180,051,352 179,016,537

Organization and Description _2

Organization and Description of the Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2022	Mar. 17, 2022	Dec. 31, 2021	Dec. 31, 2020
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Cash, cash equivalents and short term investments	$ 21,600		$ 36,400
Accumulated deficit	(161,870)		$ (144,724)	$ (115,808)
PIPE Investment [Member]
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Business acquisition, transaction costs	8,900
Sale of stock consideration received on transaction	19,000
Proceeds from sale maturity and collections of investments	$ 14,500
Number of shares issued in transaction	1,452,000
Sale of stock, price per share	$ 10
Number of securities called by each warrant or right	1
Exercise price of warrants or rights	$ 11.5
Number of days commences for share purchase after the closing and terminating on the five-year anniversary	30 days
Business combination, consideration transferred	$ 50,000
PIPE Investment [Member] | Cash [Member]
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Assets held in trust	$ 4,500
Business Combination Agreement [Member] | Combined Company [Member]
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Transaction value		$ 205,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Jan. 01, 2020 USD ($)
Deferred revenue	$ 4,601,000		$ 4,601,000		$ 3,610,000	$ 1,887,000
Short term leases term					12 months
Number of operating segments | segment			1		1
Concentration risk, credit risk off balance sheet amount	0	$ 0	$ 0	$ 0	$ 0	0
Impairment of long lived assets	0	$ 0	0	$ 0	0	0
Lease liability	312,000		312,000		510,000	1,200,000	$ 1,700,000
Right-of-use assets	$ 294,000		$ 294,000		$ 483,000	$ 1,124,000	$ 1,700,000
Operating lease, weighted average discount rate, percent	5.05%		5.05%		5.05%		5.84%
Minimum [Member] | Laboratory Equipment [Member]
Property plant and equipment useful life			2 years		2 years
Minimum [Member] | Furniture and Fixtures [Member]
Property plant and equipment useful life			2 years		2 years
Minimum [Member] | Office Equipment [Member]
Property plant and equipment useful life			2 years		2 years
Minimum [Member] | Software Development [Member]
Property plant and equipment useful life			2 years		2 years
Maximum [Member] | Laboratory Equipment [Member]
Property plant and equipment useful life			5 years		5 years
Maximum [Member] | Furniture and Fixtures [Member]
Property plant and equipment useful life			5 years		5 years
Maximum [Member] | Office Equipment [Member]
Property plant and equipment useful life			5 years		5 years
Maximum [Member] | Software Development [Member]
Property plant and equipment useful life			5 years		5 years
Prepaid Expenses and Other Current Assets [Member]
Deferred transaction costs	$ 2,300,000		$ 2,300,000		$ 500,000
Deferred offering costs					$ 400,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - Fair Value, Recurring [Member] - USD ($)	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Financial Liabilities Fair Value Disclosure	$ 2,000	$ 2,000	$ 2,000
Fair Value, Inputs, Level 3 [Member]
Financial Liabilities Fair Value Disclosure	2,000	2,000	2,000
Preferred Stock Warrant Liability [Member]
Financial Liabilities Fair Value Disclosure	2,000	2,000	2,000
Preferred Stock Warrant Liability [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Liabilities Fair Value Disclosure	$ 2,000	$ 2,000	$ 2,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Apexigen measured at fair value on a recurring basis (Detail) - Fair Value, Recurring [Member] - USD ($)	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Financial assets:
Assets, Fair Value Disclosure	$ 20,519,000	$ 31,443,000	$ 53,383,000
Financial liability:
Financial Liabilities Fair Value Disclosure	2,000	2,000	2,000
Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	2,000	2,000	2,000
Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	10,538,000	18,526,000	18,201,000
U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure	5,991,000		2,500,000
Commercial paper [Member]
Financial assets:
Assets, Fair Value Disclosure		5,498,000	21,881,000
Corporate debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure		4,512,000	7,494,000
Government debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure	3,990,000	1,503,000
Asset backed securities [Member]
Financial assets:
Assets, Fair Value Disclosure		1,404,000	3,307,000
Fair Value, Inputs, Level 1 [Member]
Financial assets:
Assets, Fair Value Disclosure	16,529,000	18,526,000	20,701,000
Financial liability:
Financial Liabilities Fair Value Disclosure	0	0	0
Fair Value, Inputs, Level 1 [Member] | Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	0	0	0
Fair Value, Inputs, Level 1 [Member] | Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	10,538,000	18,526,000	18,201,000
Fair Value, Inputs, Level 1 [Member] | U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure	5,991,000		2,500,000
Fair Value, Inputs, Level 1 [Member] | Commercial paper [Member]
Financial assets:
Assets, Fair Value Disclosure		0	0
Fair Value, Inputs, Level 1 [Member] | Corporate debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure		0	0
Fair Value, Inputs, Level 1 [Member] | Government debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Asset backed securities [Member]
Financial assets:
Assets, Fair Value Disclosure		0	0
Fair Value, Inputs, Level 2 [Member]
Financial assets:
Assets, Fair Value Disclosure	3,990,000	12,917,000	32,682,000
Financial liability:
Financial Liabilities Fair Value Disclosure	0	0	0
Fair Value, Inputs, Level 2 [Member] | Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	0	0	0
Fair Value, Inputs, Level 2 [Member] | Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	0	0	0
Fair Value, Inputs, Level 2 [Member] | U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure	0		0
Fair Value, Inputs, Level 2 [Member] | Commercial paper [Member]
Financial assets:
Assets, Fair Value Disclosure		5,498,000	21,881,000
Fair Value, Inputs, Level 2 [Member] | Corporate debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure		4,512,000	7,494,000
Fair Value, Inputs, Level 2 [Member] | Government debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure	3,990,000	1,503,000
Fair Value, Inputs, Level 2 [Member] | Asset backed securities [Member]
Financial assets:
Assets, Fair Value Disclosure		1,404,000	3,307,000
Fair Value, Inputs, Level 3 [Member]
Financial assets:
Assets, Fair Value Disclosure	0	0	0
Financial liability:
Financial Liabilities Fair Value Disclosure	2,000	2,000	2,000
Fair Value, Inputs, Level 3 [Member] | Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	2,000	2,000	2,000
Fair Value, Inputs, Level 3 [Member] | Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	0	0	0
Fair Value, Inputs, Level 3 [Member] | U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure	0		0
Fair Value, Inputs, Level 3 [Member] | Commercial paper [Member]
Financial assets:
Assets, Fair Value Disclosure		0	0
Fair Value, Inputs, Level 3 [Member] | Corporate debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure		0	0
Fair Value, Inputs, Level 3 [Member] | Government debt securities [Member]
Financial assets:
Assets, Fair Value Disclosure	$ 0	0
Fair Value, Inputs, Level 3 [Member] | Asset backed securities [Member]
Financial assets:
Assets, Fair Value Disclosure		$ 0	$ 0

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of fair value of Apexigen's marketable securities and the gross unrealized holding gains and losses (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 9,998	$ 12,921	$ 35,179
Unrealized Gains	0	0	3
Unrealized Losses	(17)	(4)	0
Estimated Fair Value	9,981	12,917	35,182
U.S. treasury securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	5,995		2,499
Unrealized Gains	0		1
Unrealized Losses	(4)		0
Estimated Fair Value	5,991		2,500
Commercial paper [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost		5,498	21,881
Unrealized Gains		0	0
Unrealized Losses		0	0
Estimated Fair Value		5,498	21,881
Corporate debt securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost		4,515	7,492
Unrealized Gains		0	2
Unrealized Losses		(3)	0
Estimated Fair Value		4,512	7,494
Government debt securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	4,003	1,503
Unrealized Gains	0	0
Unrealized Losses	(13)	0
Estimated Fair Value	3,990	1,503
Asset backed securities [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost		1,405	3,307
Unrealized Gains		0	0
Unrealized Losses		(1)	0
Estimated Fair Value		1,404	3,307
Cash [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	1,106	4,917	7,083
Unrealized Gains	0	0	0
Unrealized Losses	0	0	0
Estimated Fair Value	1,106	4,917	7,083
Money market funds [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	10,538	18,526	18,201
Unrealized Gains	0	0	0
Unrealized Losses	0	0	0
Estimated Fair Value	10,538	18,526	18,201
Total cash and cash equivalents [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	11,644	23,443	25,284
Unrealized Gains	0	0	0
Unrealized Losses	0	0	0
Estimated Fair Value	$ 11,644	$ 23,443	$ 25,284

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 959	$ 1,008	$ 979
Less: accumulated depreciation	(769)	(763)	(670)
Total property and equipment, net	190	245	309
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	894	943	909
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	28	28	28
Office equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	25	25	30
Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 12	$ 12	$ 12

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Accrued liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Accrued Liabilities [Line Items]
Accrued clinical trial and manufacturing costs	$ 5,667	$ 6,472	$ 4,818
Accrued personnel costs	1,034	1,172	1,142
Other accrued liabilities	796	844	637
Total accrued liabilities	$ 7,497	$ 8,488	$ 6,597

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Components [Abstract]
Depreciation expense for property and equipment	$ 28,000	$ 26,000	$ 55,000	$ 53,000	$ 105,000	$ 127,000

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020
Leases [Abstract]
Operating lease agreement lease term			2023-04		2023-04
Operating lease, weighted average discount rate, percent	5.05%		5.05%		5.05%		5.84%
Right-of-use assets	$ 294		$ 294		$ 483	$ 1,124	$ 1,700
Lease liability	312		312		510	1,200	$ 1,700
Rent Expense	$ 100	$ 100	$ 200	$ 300	$ 600	$ 800
Sublease contract term					one-year term
Sublease extended period					August 2021
Sublease termination period					April 2021

Leases - Summary of future mini

Leases - Summary of future minimum lease payments (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020
Lessee, Operating Lease, Liability, to be Paid [Abstract]
2022 (6 months remaining)	$ 212
2023 / 2022	106	$ 422
2023		106
Total undiscounted future lease payments	318	528
Less: imputed interest	(6)	(18)
Total lease liabilities	$ 312	$ 510	$ 1,200	$ 1,700

Convertible Preferred Stock - S

Convertible Preferred Stock - Schedule of Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Convertible Preferred Stock [Line Items]
Shares Authorized	148,570,771	148,570,771	148,570,771
Shares Issued	145,130,628	145,130,628	145,130,628
Shares Outstanding	145,130,628	145,130,628	145,130,628
Carrying Value	$ 158,707	$ 158,707	$ 158,707
Liquidation Preference	$ 160,085	$ 160,085	$ 160,085
Series A One Convertible Preferred Stock [Member]
Convertible Preferred Stock [Line Items]
Shares Authorized	39,196,116	39,196,116	39,196,116
Shares Issued	39,196,116	39,196,116	39,196,116
Shares Outstanding	39,196,116	39,196,116	39,196,116
Carrying Value	$ 19,787	$ 19,787	$ 19,787
Liquidation Preference	$ 19,990	$ 19,990	$ 19,990
Series A Two Convertible Preferred Stock [Member]
Convertible Preferred Stock [Line Items]
Shares Authorized	12,652,762	12,652,762	12,652,762
Shares Issued	12,625,343	12,625,343	12,625,343
Shares Outstanding	12,625,343	12,625,343	12,625,343
Carrying Value	$ 2,525	$ 2,525	$ 2,525
Liquidation Preference	$ 2,525	$ 2,525	$ 2,525
Series B Convertible Preferred Stock [Member]
Convertible Preferred Stock [Line Items]
Shares Authorized	14,218,546	14,218,546	14,218,546
Shares Issued	14,218,546	14,218,546	14,218,546
Shares Outstanding	14,218,546	14,218,546	14,218,546
Carrying Value	$ 14,895	$ 14,895	$ 14,895
Liquidation Preference	$ 15,000	$ 15,000	$ 15,000
Series C Convertible Preferred Stock [Member]
Convertible Preferred Stock [Line Items]
Shares Authorized	82,503,347	82,503,347	82,503,347
Shares Issued	79,090,623	79,090,623	79,090,623
Shares Outstanding	79,090,623	79,090,623	79,090,623
Carrying Value	$ 121,500	$ 121,500	$ 121,500
Liquidation Preference	$ 122,570	$ 122,570	$ 122,570

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Dividends declared	$ 0	$ 0
Minimum gross proceeds required for conversion of preferred stock	$ 30,000,000	$ 30,000,000
Percentage of outstanding shares of holders of preferred stock required as conversion basis	50%	50%
Series A-1 convertible preferred stock [Member]
Class of Stock [Line Items]
Noncumulative dividends annual rate	$ 0.0408	$ 0.0408
Series A-2 convertible preferred stock [Member]
Class of Stock [Line Items]
Noncumulative dividends annual rate	0.016	0.016
Series B convertible preferred stock [Member]
Class of Stock [Line Items]
Noncumulative dividends annual rate	0.0844	0.0844
Series C convertible preferred stock [Member]
Class of Stock [Line Items]
Noncumulative dividends annual rate	0.124	0.124
Number of shares issued			8,602,082
Gross proceeds from issaunce of shares			$ 13,300,000
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Liquidation preference value per share	1.54974	1.54974
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Liquidation preference value per share	1.05496	1.05496
Series A-1 Preferred Stock [Member]
Class of Stock [Line Items]
Liquidation preference value per share	0.51	0.51
Series A-2 Preferred Stock [Member]
Class of Stock [Line Items]
Liquidation preference value per share	$ 0.2	$ 0.2

Common Stock - Summary of Commo

Common Stock - Summary of Common Stock (Detail) - shares	Jun. 30, 2022	Dec. 31, 2021
Common stock reserved for issuance	188,064,720	188,455,544
Series A-1 convertible preferred stock [Member]
Common stock reserved for issuance	39,196,116	39,196,116
Series A-2 convertible preferred stock [Member]
Common stock reserved for issuance	12,625,343	12,625,343
Series B convertible preferred stock [Member]
Common stock reserved for issuance	14,218,546	14,218,546
Series C convertible preferred stock [Member]
Common stock reserved for issuance	79,090,623	79,090,623
Options issued and outstanding [Member]
Common stock reserved for issuance	33,755,492	34,522,687
Options available for future grants [Member]
Common stock reserved for issuance	9,048,183	8,671,812
Common stock warrants [Member]
Common stock reserved for issuance	102,998	102,998
Series A-2 preferred stock warrant [Member]
Common stock reserved for issuance	27,419	27,419

Clinical Study Agreement Amen_2

Clinical Study Agreement Amendment With Parker Institute - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2019	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Clinical Study Agreement Amendment with Parker Institute [Line Items]
Research and Development Expense		$ 6,005,000	$ 4,658,000	$ 13,113,000	$ 9,621,000	$ 21,664,000	$ 18,770,000
Parker Institute for Cancer Immunotherapy [Member]
Clinical Study Agreement Amendment with Parker Institute [Line Items]
cash		9,500,000		9,500,000
Collaboration Agreement [Member] | Parker Institute for Cancer Immunotherapy [Member]
Clinical Study Agreement Amendment with Parker Institute [Line Items]
cash	$ 1,000,000					9,600,000
Number of stock issued during the period.	1,290,540
Research and Development Expense	$ 900,000	$ 0	$ 0	$ 0	$ 0	$ 0	$ 700,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Based Compensation Expense Related To Stock Options Granted (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 368	$ 262	$ 789	$ 622	$ 1,143,000	$ 1,345,000
Research and development [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	139	54	258	186	292,000	531,000
General and administrative [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 229	$ 208	$ 531	$ 436	$ 851,000	$ 814,000

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Share Based Payment Award Stock Options Valuation Assumptions (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, Minimum		75%
Expected volatility, Maximum		82%
Expected volatility	88%
Risk-free interest rate, Minimum	0.60%	0.27%
Risk-free interest rate, Maximum	1.20%	1.51%
Expected dividend	0%	0%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	5 years 7 months 13 days	5 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	10 years	10 years

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Share Based Payment Award Stock Options Valuation Assumptions Pricing Model (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	88%
Risk-free interest rate, Minimum	0.60%	0.27%
Risk-free interest rate, Maximum	1.20%	1.51%
Expected dividend	0%	0%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	5 years 7 months 13 days	5 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	10 years	10 years
Repriced Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	80%
Risk-free interest rate, Minimum	0.18%
Risk-free interest rate, Maximum	0.34%
Expected dividend	0%
Repriced Stock Options [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	4 years 3 months 3 days
Repriced Stock Options [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	6 years 5 months 19 days

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock Options Activity Under the Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Share-based Payment Arrangement, Disclosure [Abstract]
Outstanding, Options Available to Grant, Beginning balance	8,671,812	8,371,662	8,371,662
Granted, Options Available to Grant			(1,545,000)
Exercised, Options Available to Grant			0
Cancelled, Options Available to Grant			1,845,150
Outstanding, Options Available to Grant, Ending balance			8,671,812
Outstanding, Number of Options Outstanding, Beginning balance	34,522,687	35,371,809	35,371,809
Granted, Number of Options Outstanding	5,397,344	1,545,000	1,545,000
Exercised, Number of Options Outstanding			(548,972)
Cancelled, Number of Options Outstanding			(1,845,150)
Outstanding, Ending balance, Number of Options Outstanding			34,522,687
Vested and exercisable, Number of Options Outstanding			30,442,623
Vested and expected to vest, Number of Options Outstanding			34,372,687
Outstanding, Weighted Average Exercise Price, Beginning balance	$ 0.28	$ 0.27	$ 0.27
Granted, Weighted Average Exercise Price	$ 0.51	$ 0.47	0.47
Exercised, Weighted Average Exercise Price			0.18
Cancelled, Weighted Average Exercise Price			0.39
Outstanding, Weighted Average Exercise Price, Ending balance			0.28
Vested and exercisable, Weighted Average Exercise Price			0.25
Vested and expected to vest, Weighted Average Exercise Price			$ 0.28
Outstanding, Weighted Average Remaining Contractual Terms (Years)			5 years 25 days
Vested and exercisable, Weighted Average Remaining Contractual Terms (Years)			4 years 7 months 17 days
Vested and expected to vest, Weighted Average Remaining Contractual Terms (Years)			5 years 18 days
Outstanding, Aggregate Intrinsic Value			$ 7,095
Vested and exercisable, Aggregate Intrinsic Value			7,052
Vested and expected to vest, Aggregate Intrinsic Value			$ 7,095

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)			3 Months Ended			6 Months Ended		12 Months Ended
	Feb. 01, 2021	Aug. 06, 2020	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Common stock, capital shares reserved for future issuance			188,064,720			188,064,720		188,455,544
Share-based compensation arrangement by share-based payment award, Award vesting period						4 years		4 years
Share-Based compensation arrangement by share-based payment award, Expiration period						10 years		10 years
Number of options vested					50,000
Share-based payment arrangement, Expense			$ 368	$ 262		$ 789	$ 622	$ 1,143,000	$ 1,345,000
Share-based payment arrangement, Nonvested award, Cost not yet recognized, Amount			$ 60,000			$ 60,000		$ 60,000	$ 1,500,000
Number of share options (or share units) granted during the period						5,397,344	1,545,000	1,545,000
Weighted average exercise price						$ 0.51	$ 0.47	$ 0.47
Share-based compensation arrangement by share-based payment award, Options, Vested in period						$ 1.9	$ 0.5
Weighted average grant-date fair value of options granted								$ 0.35	$ 0.44
Share-based compensation arrangement by share-based payment award, Options, Expirations in period						5,773,715	1,737,530
Share-based compensation arrangement by share-based payment award, Options, Exercises in Period, Intrinsic value							$ 200,000	$ 200,000
Share-based payment arrangement, Nonvested award, Cost not yet recognized, Period for recognition						2 years 8 months 12 days		1 year 9 months 18 days	1 year 10 months 24 days
Weighted average exercise price								$ 0.28	$ 0.27
Weighted average grant date fair value of options			$ 0.36	$ 0.35		$ 0.36	$ 0.35
Unrecognized incremental compensation cost						$ 2.6		$ 40,000
Minimum [Member]
Weighted average exercise price		$ 0.67
Maximum [Member]
Weighted average exercise price		$ 0.74
Incentive Stock Option [Member]
Common stock, capital shares reserved for future issuance			42,803,675			42,803,675		43,194,499
Percentage of stock option granted to stockholder						10%		10%
Nonstatutory Stock Option [Member] | Minimum [Member]
Percentage of the estimated fair value of the shares on the date of grant						100%		100%
Nonstatutory Stock Option [Member] | Maximum [Member]
Percentage of the estimated fair value of the shares on the date of grant						110%		110%
Stock Option [Member]
Share-based compensation arrangement by share-based payment award, Award vesting period	10 years
Number of shares purchased for issuance under share-based payment arrangement	200,000
Repriced Stock Options [Member]
Share-based payment arrangement, Expense		$ 26,000			$ 20,000			$ 31,000	$ 28,000
Number of options for which repricing approved for various employees		4,438,847
Weighted average exercise price		$ 0.47
Weighted average grant date fair value of options		$ 0.31
Unrecognized incremental compensation cost		$ 156,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Commitments [Line Items]
Proceeds from Royalties Received	$ 3.6	$ 1.9
Licensing Agreements [Member]
Other Commitments [Line Items]
Business Combination, Contingent Consideration, Liability, Noncurrent	0.4	0.2
Abcam [Member]
Other Commitments [Line Items]
Business Combination, Contingent Consideration, Liability, Noncurrent	$ 0.4	$ 0.4

Income Taxes - Schedule Of Rec

Income Taxes - Schedule Of Reconciliation Of Effective Tax Rate Of The Provision For Income Taxes (Detail)	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory income tax rate	21%		21%	21%
Permanent differences			(0.30%)	(0.50%)
Other credit			3.20%	1.70%
Other			(0.30%)	0.60%
State rate change impact			0%	(21.00%)
Change in valuation allowance			(23.60%)	(1.80%)
Effective tax rate	0%	0%	0%	0%

Income Taxes - Summary of com

Income Taxes - Summary of components of the deferred tax assets and liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carry forwards	$ 27,217	$ 21,135
Tax credits	3,964	3,049
Other reserves and accruals	1,334	1,641
Gross deferred tax assets	32,515	25,825
Deferred tax liabilities:
Depreciation and amortization	(24)	(32)
Right-of-use assets	(101)	(236)
Gross deferred tax liabilities	(125)	(268)
Valuation allowance	(32,390)	(25,557)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Summary of Re

Income Taxes - Summary of Reconciliation Of The Beginning And Ending Amounts Of Unrecognized Tax Benefits (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Uncertainties [Abstract]
Gross unrecognized tax benefit at January 1	$ 1,181	$ 966
Additions for tax provision taken in the current year	417	215
Gross unrecognized tax benefit at December 31	$ 1,598	$ 1,181

Income Taxes - Additional Inf

Income Taxes - Additional Information (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Mar. 27, 2020
Provision for income taxes			$ 0	$ 0
Valuation allowance inreased amount during the period			6,800,000	$ 400,000
Federal Orphan Drug credits			$ 500,000
Federal Orphan Drug credits expiration period			2041
Effective tax rate	0%	0%	0%	0%
U.S. federal statutory rate	21%		21%	21%
Period Beginning Before Two Thousand Twenty One [Member]
As per cares act permits operating loss carryforwards and carrybaks to offset percentage of taxable income					100%
Domestic Tax Authority [Member]
Net operating loss caryforwards			$ 129,600,000
Percentage of limitations on the use of operating loss carryforwards available to reduce future taxable income			80%
Operating Loss Carryforwards Expiration Period			2033
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax credit carryforward amount			$ 3,100,000
Tax credit carryforward expiration period			2030
Domestic Tax Authority [Member] | Indefinitely [Member]
Net operating loss caryforwards			$ 101,400,000
Domestic Tax Authority [Member] | Two Thousand And Thirty Three [Member]
Net operating loss caryforwards			$ 28,300,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards Expiration Period			2035
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax credit carryforward amount			$ 2,300,000
State and Local Jurisdiction [Member] | Two Thousand And Thirty Five [Member]
Net operating loss caryforwards			$ 64,500,000

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Diluted Net Loss Per Share for the Periods Presented Due To Their Anti-Dilutive Effect (Detail) - shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	179,016,537	180,051,352
Series A-1 convertible preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	39,196,116	39,196,116
Series A-2 convertible preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	12,625,343	12,625,343
Series B convertible preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	14,218,546	14,218,546
Series C convertible preferred stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	79,090,623	79,090,623
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	33,755,492	34,790,307
Common stock warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	102,998	102,998
Series A-2 preferred stock warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock reserved for issuance	27,419	27,419

401(k) Plan - Additional Inform

401(k) Plan - Additional Information (Detail) - 401(k) retirement plan [Member] - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Contribution Plan Disclosure [Line Items]
Percentage of contributions by employees of their eligible compensation subject to maximum allowed by law	100%
Defined contribution employer matches employee contributions Maximum Percentage of their salary	4%
Defined Contribution Plan Expenses Recognized Amount	$ 139,000	$ 128,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
	Jan. 23, 2022	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Mar. 17, 2022	Dec. 31, 2020
Subsequent Event [Line Items]
Stock option grants				8,671,812		8,371,662
Sahe based compensation,Number of shares granted		5,397,344	1,545,000	1,545,000
Subsequent Event [Member] | Combined Company [Member]
Subsequent Event [Line Items]
Transaction value					$ 205
Subsequent Event [Member] | Share-based Payment Arrangement, Option [Member]
Subsequent Event [Line Items]
Stock option grants	5,007,000
Sahe based compensation,Number of shares granted	110,344