Fair Value Measurement - Summary of Apexigen measured at fair value on a recurring basis (Detail) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financial assets:
Assets, Fair Value Disclosure	$ 9,549	$ 16,668
Financial liability:
Financial Liabilities Fair Value Disclosure	10	11
Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure		11
Derivative Warrant Liabilities [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	10
Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	9,549	14,671
U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure		1,997
Fair Value, Inputs, Level 1 [Member]
Financial assets:
Assets, Fair Value Disclosure	9,549	16,668
Financial liability:
Financial Liabilities Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure		0
Fair Value, Inputs, Level 1 [Member] | Derivative Warrant Liabilities [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	0
Fair Value, Inputs, Level 1 [Member] | Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	9,549	14,671
Fair Value, Inputs, Level 1 [Member] | U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure		1,997
Fair Value, Inputs, Level 2 [Member]
Financial assets:
Assets, Fair Value Disclosure	0	0
Financial liability:
Financial Liabilities Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] | Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure		0
Fair Value, Inputs, Level 2 [Member] | Derivative Warrant Liabilities [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	0
Fair Value, Inputs, Level 2 [Member] | Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member] | U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure		0
Fair Value, Inputs, Level 3 [Member]
Financial assets:
Assets, Fair Value Disclosure	0	0
Financial liability:
Financial Liabilities Fair Value Disclosure	10	11
Fair Value, Inputs, Level 3 [Member] | Preferred stock warrant liability [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure		11
Fair Value, Inputs, Level 3 [Member] | Derivative Warrant Liabilities [Member]
Financial liability:
Financial Liabilities Fair Value Disclosure	10
Fair Value, Inputs, Level 3 [Member] | Money market funds [Member]
Financial assets:
Assets, Fair Value Disclosure	$ 0	0
Fair Value, Inputs, Level 3 [Member] | U.S. treasury securities [Member]
Financial assets:
Assets, Fair Value Disclosure		$ 0