Income Taxes - Schedule of the Tax Effects of Temporary Differences and Carry-Forwards That Give Rise to Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax assets:
Accounts payable and accrued expenses	$ 714	$ 1,215
Accrued payroll and related expenses	2,315	1,691
Stock-based compensation expense	2,336	3,508
Depreciation of property and equipment	853	1,711
Capitalized software	119	0
Unbilled receivables and refund liabilities	97	1,811
Operating loss carry-forwards of foreign subsidiary	9,484	11,000
Federal operating loss carry-forwards	17,109	17,161
State operating loss carry-forwards	4,537	3,591
Other	1,624	376
Gross deferred tax assets	39,188	42,064
Less valuation allowance	31,597	34,776
Gross deferred tax assets net of valuation allowance	7,591	7,288
Deferred income tax liabilities:
Intangible assets	1,269	1,987
Capitalized software	0	29
Other	3,427	3,734
Gross deferred tax liabilities	4,696	5,750
Net deferred tax assets	$ 2,895	$ 1,538