Property and Equipment, Net - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Right-of-use assets under finance leases	$ 1,866	$ 1,854
Total	44,557	24,534
Less: accumulated depreciation and amortization	(17,710)	(13,186)
Property and equipment, net	26,847	11,348
Computer software and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	21,234	13,038
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,504	2,376
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 16,953	$ 7,266