Stock-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of common stock per share	$ 0.98
Weighted-average grant-date fair value of options granted	$ 0.78	$ 2.32
Aggregate intrinsic value of stock options exercised	$ 0	$ 200,000
Gross unrecognized stock-based compensation expense	$ 11,000,000
Unrecognized stock-based compensation expense weighted average amortized period	1 year 11 months 8 days
Restricted Stock Units ('RSU')
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense weighted average amortized period	2 years 4 months 24 days
Gross unrecognized stock-based compensation expense	$ 5,040,000.00
Issuance of restricted common units, net of tax withholdings, (Shares)	22,728
Restricted common units issued, gross	30,892
2022 Equity Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	413,537
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	4,072,703
2019 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	132,435
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	653,777
Number of shares issued	29,619
Apexigen Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for future issuance	764,154

Fair value of common stock per share.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Number of shares issued under share-based payment arrangement.

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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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