Organization, Business and Basis of Presentation - Additional Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($) Segment	Dec. 31, 2020 USD ($)
Description Of Business [Line Items]
Accumulated deficit	$ 372,296	$ 338,528
Cash, cash equivalents and available-for-sale investments	107,900
Other receivables	$ 435	$ 2,039
Number of operating segment \| Segment	1
Pangu BioPharma [Member] \| Hong Kong [Member]
Description Of Business [Line Items]
Majority-owned subsidiary percentage	98.00%

The cumulative amount of the reporting entity's undistributed earnings or deficit.

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