Property and Equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 24,052	$ 19,210
Less accumulated depreciation	(15,964)	(11,678)
Net property and equipment	8,088	7,532
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,844	9,858
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,131	2,409
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 8,077	$ 6,943