Intangible Assets - Schedule of Patent Cost and Other Asset (Detail) - Patents [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Patent costs	$ 2,525	$ 2,721
Accumulated amortization	(1,583)	(1,689)
Finite-lived intangible assets, net	$ 942	$ 1,032