Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 10,499	$ 7,256
Less accumulated depreciation and amortization	(5,849)	(4,460)
Property and equipment, net	4,650	2,796
Furniture and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,189	1,127
Property and equipment, useful life in years	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 2,776	727
Property and equipment, useful life in years	5 years
Systems Hardware
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,404	1,623
Property and equipment, useful life in years	5 years
Office Computers
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 3,745	2,586
Property and equipment, useful life in years	3 years
Computer and System Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,385	$ 1,193
Property and equipment, useful life in years	3 years