Balance Sheet Components - Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 43,088	$ 38,551
Less: accumulated depreciation and amortization	(21,883)	(17,767)
Property and equipment, net	21,205	20,784
Computers
Property, Plant and Equipment [Line Items]
Total property and equipment	11,152	9,249
Capitalized internal-use software
Property, Plant and Equipment [Line Items]
Total property and equipment	13,549	10,041
Office equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	3,213	2,770
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	9,391	9,472
Motor vehicles
Property, Plant and Equipment [Line Items]
Total property and equipment	1,499	2,423
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	4,274	4,274
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 10	$ 322