Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment	$ 10,700	$ 4,306
Less accumulated depreciation	(1,276)	(1,436)
Property and equipment, net	9,424	2,870
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment	291	216
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	9,431	3,210
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	$ 978	$ 880