Patents and Other Intangible Assets - Schedule of Patents and Other Intangibles Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	$ 46,278	$ 42,324
Accumulated amortization	(38,817)	(37,022)
Patents and other intangible assets, net	7,461	5,302
Patents [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	38,348	36,847
Accumulated amortization	(34,717)	(33,297)
Trademarks—finite lived [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	319	120
Accumulated amortization	(138)	(120)
Licenses and other [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	7,611	5,357
Accumulated amortization	$ (3,962)	$ (3,605)