Accrued Expenses and Other Liabilities - Components of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Components of accrued liabilities
Accrued bonuses	$ 4,218	$ 5,590
Accrued payroll related liabilities	1,888	3,277
Accrued vacation	2,952	2,497
Accrued commissions	722	825
Accrued software expense	463	675
Accrued contractor fees	341	346
Accrued professional service fees	1,511	341
Deferred rent	60	64
Income tax related accruals	531	189
Other accrued expenses	1,061	1,180
Total	$ 13,747	$ 14,984