Balance Sheet Components - Schedule of Deferred Revenue (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Revenue [Line Items]
Total deferred revenue	$ 12,666	$ 14,010
Less: current portion of deferred revenue	(10,094)	(10,457)
Noncurrent portion of deferred revenue	2,572	3,553
Product
Deferred Revenue [Line Items]
Total deferred revenue	1,888	3,141
Service
Deferred Revenue [Line Items]
Total deferred revenue	8,857	8,473
Distribution Rights
Deferred Revenue [Line Items]
Total deferred revenue	$ 1,921	$ 2,396