Summary of Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Manufacturing-related deposits and prepaids	$ 87,802	$ 134,430
Collaboration receivable	17,685	34,184
Prepaid clinical and pre-clinical expenses	13,228	16,224
Prepaid maintenance services	6,695	6,411
Prepaid research expenses	4,738	5,854
Leasehold improvement receivable	3,059	3,059
Prepaid insurance	2,660	4,158
Prepaid income tax	894	4,939
Other	4,905	4,065
Total other current assets	$ 141,666	$ 213,324