Patents and Other Intangible Assets - Schedule of Patents and Other Intangibles Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	$ 43,389	$ 43,188
Accumulated amortization	(34,871)	(34,142)
Patents and other intangible assets, net	8,518	9,046
Patents [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	36,496	36,320
Accumulated amortization	(32,351)	(31,739)
Trademarks-definite lived [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	645	620
Accumulated amortization	(484)	(454)
Licenses and other [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	6,248	6,248
Accumulated amortization	$ (2,036)	$ (1,949)