Prepaid Expenses - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid expenses	$ 13,018	$ 12,076
Prepaid R&D clinical costs	10,557	11,286
Prepaid insurance	2,007	223
Other prepaid costs	$ 454	$ 567