Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation expense related to plant and equipment	$ 618,000	$ 626,000	$ 814,000
Amount disposed of property plant and equipment	238,000	378,000	345,000
Gain or loss on disposal of property plant and equipment	$ 10,000	$ 0	$ (9,000)