Income Taxes - Loss Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (111,101)	$ (41,720)	$ (78,124)
Foreign	1,276	1,293	973
Net loss before provision for income taxes	$ (109,825)	$ (40,427)	$ (77,151)