Balance Sheet Components - Components of Inventory and Printed Circuit Board Assemblies ("PCBAs") (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Total inventory and printed circuit board assemblies	$ 4,037	$ 2,062
Other assets	7,940	3,208
Raw materials
Inventory [Line Items]
Total inventory and printed circuit board assemblies	1,574	676
Finished goods
Inventory [Line Items]
Total inventory and printed circuit board assemblies	2,463	1,386
Printed Circuit Board Assemblies
Inventory [Line Items]
Amortization	3,600	3,100	$ 2,100
Other assets	$ 7,400	$ 2,500