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	$ 43,208		$ 43,188
Accumulated amortization	(34,690)		(34,142)
Patents and other intangible assets, net	8,518	[1]	9,046
Patents [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Cost	34,815		34,820
Accumulated amortization	(32,170)		(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	7,748		7,748
Accumulated amortization	$ (2,036)		$ (1,949)

[1] Unaudited