Intangible Assets and Related Accumulated Amortization (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Intangible Assets And Goodwill [Line Items]
Intangible assets, gross	$ 2,800	$ 2,800
Intangible assets, accumulated amortization	(2,735)	(2,686)
Intangible assets, net	65	114
Goodwill gross	2,926	2,926
Goodwill	2,926	2,926
Patents
Intangible Assets And Goodwill [Line Items]
Intangible assets, gross	1,914	1,914
Intangible assets, accumulated amortization	$ (1,914)	(1,907)
Intangible assets, net		7
Patents | Minimum
Intangible Assets And Goodwill [Line Items]
Useful life	4 years
Patents | Maximum
Intangible Assets And Goodwill [Line Items]
Useful life	10 years
Trademarks
Intangible Assets And Goodwill [Line Items]
Useful life	6 years
Intangible assets, gross	$ 69	69
Intangible assets, accumulated amortization	(69)	(69)
Other Intangible Assets
Intangible Assets And Goodwill [Line Items]
Intangible assets, gross	817	817
Intangible assets, accumulated amortization	(752)	(710)
Intangible assets, net	$ 65	$ 107
Other Intangible Assets | Minimum
Intangible Assets And Goodwill [Line Items]
Useful life	4 years
Other Intangible Assets | Maximum
Intangible Assets And Goodwill [Line Items]
Useful life	6 years