Quarterly Financial Data - Summarized Quarterly Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Selected Quarterly Financial Information [Abstract]
Revenues	$ 11,843	$ 8,746	$ 10,484	$ 11,602	$ 12,032	$ 11,012	$ 10,171	$ 10,114	$ 42,675	$ 43,329	$ 57,767
Gross profit	9,473	6,254	8,083	9,158	9,695	8,892	8,375	7,919	32,968	34,881	44,006
Operating (loss)	(1,501)	(12,980)	(7,248)	(6,101)	(4,555)	(6,007)	(6,824)	(9,615)	(27,830)	(27,001)	(165,666)
Net (loss)	$ (1,502)	$ (13,049)	$ (7,244)	$ (6,158)	$ (4,143)	$ (4,813)	$ (6,825)	$ (9,682)	$ (27,953)	$ (25,463)	$ (159,606)
Net (loss) per share, basic	$ (0.04)	$ (0.35)	$ (0.19)	$ (0.17)	$ (0.12)	$ (0.13)	$ (0.19)	$ (0.27)	$ (0.76)	$ (0.71)	$ (4.48)
Weighted average shares outstanding, basic	37,027	37,036	37,247	36,614	35,882	35,879	36,045	35,590	36,982	35,849	35,617
Net (loss) per share, diluted	$ (0.04)	$ (0.35)	$ (0.19)	$ (0.17)	$ (0.12)	$ (0.13)	$ (0.19)	$ (0.27)	$ (0.76)	$ (0.71)	$ (4.48)
Weighted average shares outstanding, diluted	37,027	37,036	37,247	36,614	35,882	35,879	36,045	35,590	36,982	35,849	35,617