Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Significant Accounting Policies [Line Items]
Net loss	$ (12,420)	$ (10,391)	$ (24,573)	$ (17,542)
Accumulated deficit	(396,869)		(396,869)		$ (372,296)
Cash, cash equivalents, restricted cash and available-for-sale investments	89,300		89,300
Restricted cash	$ 733		$ 733
Pangu BioPharma [Member] | Hong Kong [Member]
Significant Accounting Policies [Line Items]
Majority-owned subsidiary percentage	98.00%		98.00%