Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 14,769	$ 14,451
Accumulated depreciation	(12,764)	(12,035)
Property and equipment, net	2,005	2,416
Building and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,828	1,884
Furniture, Fixtures and Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	2,119	2,002
Plant and Machinery
Property Plant And Equipment [Line Items]
Property and equipment, gross	8,944	8,848
Purchased Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,878	$ 1,717