Income Taxes - Components of Provision for (Benefit from) Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current tax provision (benefit):
Foreign	$ 59	$ 85	$ (180)
Total current tax provision (benefit)	59	85	(180)
Deferred tax provision (benefit):
Foreign	83	(245)	(122)
Total deferred tax provision (benefit)	83	(245)	(122)
Total provision for (benefit from) income taxes	$ 142	$ (160)	$ (302)