Prepaid Expenses - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid expenses	$ 12,076	$ 8,863
Prepaid R&D clinical costs	11,286	8,498
Prepaid insurance	223	181
Other prepaid costs	$ 567	$ 184