Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Total property and equipment	$ 58,820	$ 49,776
Less accumulated depreciation and amortization	(29,927)	(22,388)
Total	28,893	27,388
Computer and Office Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	7,598	6,204
Purchased Software
Property Plant And Equipment [Line Items]
Total property and equipment	1,071	1,071
Capitalized Software Development Costs
Property Plant And Equipment [Line Items]
Total property and equipment	27,643	22,181
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	5,105	4,688
Leasehold Improvements and Other
Property Plant And Equipment [Line Items]
Total property and equipment	$ 17,403	$ 15,632