Balance Sheet Components - Schedule of Deferred Revenue (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Deferred Revenue [Line Items]
Total deferred revenue	$ 24,722	$ 14,010
Less: current portion of deferred revenue	(21,838)	(10,457)
Noncurrent portion of deferred revenue	2,884	3,553
Product
Deferred Revenue [Line Items]
Total deferred revenue	14,329	3,141
Service
Deferred Revenue [Line Items]
Total deferred revenue	8,353	8,473
Distribution Rights
Deferred Revenue [Line Items]
Total deferred revenue	$ 2,040	$ 2,396