Quarterly Financial Data - Summarized Quarterly Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 10,006	$ 9,586	$ 9,386	$ 10,529	$ 10,554	$ 9,448	$ 8,528	$ 8,449	$ 39,507	$ 36,979	$ 42,675
Gross profit	8,002	7,627	7,315	8,411	8,309	7,247	6,077	6,029	31,355	27,662	32,968
Operating income (loss)	(547)	(768)	(1,225)	2	217	(1,144)	(5,681)	(5,134)	(2,538)	(11,742)	(27,830)
Net income (loss)	$ (591)	$ (770)	$ (1,231)	$ (10)	$ 205	$ (1,142)	$ (5,695)	$ (5,167)	$ (2,602)	$ (11,799)	$ (27,953)
Net (loss) per share, basic	$ (0.01)	$ (0.02)	$ (0.03)	$ 0.00	$ 0.00	$ (0.03)	$ (0.15)	$ (0.14)	$ (0.06)	$ (0.29)	$ (0.76)
Weighted average shares outstanding, basic	45,860	46,160	46,257	45,501	45,053	41,225	38,518	37,714	45,946	40,649	36,982
Net (loss) per share, diluted	$ (0.01)	$ (0.02)	$ (0.03)	$ 0.00	$ 0.00	$ (0.03)	$ (0.15)	$ (0.14)	$ (0.06)	$ (0.29)	$ (0.76)
Weighted average shares outstanding, diluted	45,860	46,160	46,257	45,501	45,053	41,225	38,518	37,714	45,946	40,649	36,982