Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Description Of Business [Line Items]
Net loss	$ (11,951)	$ (12,153)
Accumulated deficit	(429,585)		$ (417,634)
Cash, cash equivalents, restricted cash and available-for-sale investments	117,600
Restricted cash	$ 3,190	$ 0	$ 3,165
Pangu BioPharma [Member] | Hong Kong [Member]
Description Of Business [Line Items]
Majority-owned subsidiary percentage	98.00%