Income Taxes - Schedule of Components of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred income tax assets:
Net operating loss carryforwards	$ 103,188	$ 101,763
Stock-based compensation	10,954	13,227
Accrued expenses	2,261	1,950
Research and development tax credits	569	569
Operating leases liabilities	10,724	0
Other	619	656
Gross deferred tax assets	128,315	118,165
Valuation allowance	(111,193)	(109,625)	$ (107,046)	$ (115,689)
Net deferred tax assets	17,122	8,540
Deferred tax liabilities:
Property, equipment and software	(3,800)	(3,477)
Intangible assets and goodwill	(4,075)	(4,274)
Capitalized commissions	(692)	(791)
§481(a) Adjustment - ASC 606	(380)	(566)
Operating lease assets	(8,958)
Gross deferred tax liabilities	(17,905)	(9,108)
Total net deferred tax liabilities	$ (783)	$ (568)