Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Total property and equipment	$ 194,739	$ 135,674
Accumulated depreciation and amortization	(41,992)	(32,412)
Property and Equipment, net	152,747	103,262
Computer and Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	27,725	23,834
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	141,859	93,239
Website and Internal-Use Software
Property Plant And Equipment [Line Items]
Total property and equipment	6,510	6,510
Office Equipment and Furniture
Property Plant And Equipment [Line Items]
Total property and equipment	$ 18,645	$ 12,091