Property and Equipment, Net of Accumulated Depreciation (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,900	$ 2,700
Less accumulated depreciation	(1,700)	(1,500)
Property and equipment, net	$ 1,218	$ 1,247