Collaboration Agreement - Summary of Collaboration Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration revenue	$ 72,649	$ 16,319	$ 107,249	$ 20,974