Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred income tax assets:
Accounts payable and accrued expenses	$ 2,088	$ 1,770
Accrued payroll and related expenses	3,902	2,998
Stock-based compensation expense	9,221	8,700
Depreciation of property and equipment	3,746	3,861
Non-compete agreements	27	50
Operating loss carry-forwards of foreign subsidiary	1,501	1,422
Federal operating loss carry-forwards	27,494	26,332
Intangible assets	6,195	11,935
State operating loss carry-forwards	2,648	2,625
Other	3,243	3,630
Gross deferred tax assets	60,065	63,323
Less valuation allowance	48,489	51,630
Gross deferred tax assets net of valuation allowance	11,576	11,693
Deferred income tax liabilities:
Intangible assets	5,790	7,405
Unbilled receivables and refund liabilities	2,538	1,781
Capitalized software	969	974
Other	675	679
Gross deferred tax liabilities	9,972	10,839
Net deferred tax assets	$ 1,604	$ 854