Balance Sheet Components - Schedule of Deferred Revenue (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	$ 23,389	$ 10,433
Less: current portion of deferred revenue	(20,151)	(6,515)
Noncurrent portion of deferred revenue	3,238	3,918
Product
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	18,861	5,050
Services
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	1,182	1,561
Distribution Rights
Deferred Revenue Arrangement [Line Items]
Total deferred revenue	$ 3,346	$ 3,822