Summary of Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Prepaid Expense And Other Assets Current [Abstract]
Manufacturing-related deposits and prepaids	$ 54,276	$ 39,036
Prepaid clinical and pre-clinical expenses	8,263	9,706
Prepaid maintenance services	4,366	2,994
Leasehold improvement receivable	3,059	13,474
Prepaid insurance	2,573	1,006
Prepaid income tax	2,114	2,130
Prepaid research expenses	2,007	1,932
Other	5,249	7,504
Total other current assets	$ 81,907	$ 77,782