United States and Foreign Components of Consolidated Loss before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S.	$ (61,246)	$ (71,946)	$ (58,048)
Foreign	1,673	965	713
Loss before income taxes	$ (59,573)	$ (70,981)	$ (57,335)