Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Components of accrued liabilities
Accrued vacation	$ 2,200	$ 1,838
Accrued payroll related liabilities	2,057	1,364
Accrued bonuses	1,375	2,245
Accrued software expense	1,147	1,668
Accrued sales and use tax	1,047	1,482
Income tax related accruals	991	498
Accrued commissions	794	2,229
Short-term portion of lease abandonment accrual	580	580
Deferred rent	536	526
Other accrued expenses	2,048	1,850
Total	$ 12,775	$ 14,280