PROPERTY AND EQUIPMENT - SCHEDULE OF PROPERTY AND EQUIPMENT (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, total	$ 9,060	$ 9,234
Less accumulated depreciation	(6,520)	(6,084)
Property and equipment, net	2,540	3,150
Computer equipment and purchased software
Property, Plant and Equipment [Line Items]
Property and equipment, total	3,151	3,206
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, total	843	834
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, total	1,146	1,274
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, total	$ 3,920	$ 3,920