Property and Equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 45,090	$ 40,449
Less: accumulated depreciation	(34,050)	(29,591)
Less: held for sale, net	0	(247)
Property and equipment, net	11,040	10,611
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	15,752	15,345
Software
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	24,120	20,381
Software development-in-progress
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	1,235	584
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	971	1,239
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 3,012	$ 2,900