Accrued Expenses and Other Liabilities - Components of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Components of accrued liabilities
Accrued bonuses	$ 4,131	$ 3,053
Accrued payroll related liabilities	2,041	2,614
Accrued vacation	2,831	2,243
Accrued commissions	955	2,537
Accrued software expense	865	844
Accrued contractor fees	447	455
Accrued professional service fees	391	344
Income tax related accruals	597	166
Other accrued expenses	1,439	1,241
Total	$ 13,697	$ 13,497