Quarterly Financial Data (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summarized quarterly information
Revenues	$ 12,032	$ 11,012	$ 10,171	$ 10,114	$ 11,239	$ 12,632	$ 16,105	$ 17,791	$ 43,329	$ 57,767	$ 130,501
Gross profit	9,695	8,892	8,375	7,919	8,513	8,933	12,545	14,015	34,881	44,006	114,994
Operating (loss)	(4,555)	(6,007)	(6,824)	(9,615)	(11,625)	(127,983)	(13,046)	(13,012)	(27,001)	(165,666)	18,381
Net income (loss)	$ (4,143)	$ (4,813)	$ (6,825)	$ (9,682)	$ (9,525)	$ (134,481)	$ (7,847)	$ (7,753)	$ (25,463)	$ (159,606)	$ 12,346
Net (loss) per share, basic (1)	$ (0.12)	$ (0.13)	$ (0.19)	$ (0.27)	$ (0.27)	$ (3.76)	$ (0.22)	$ (0.22)	$ (0.71)	$ (4.48)	$ 0.36
Weighted average shares outstanding - basic	35,882	35,879	36,045	35,590	35,696	35,728	35,775	35,263	35,849	35,617	34,204
Net (loss) per share, diluted (1)	$ (0.12)	$ (0.13)	$ (0.19)	$ (0.27)	$ (0.27)	$ (3.76)	$ (0.22)	$ (0.22)	$ (0.71)	$ (4.48)	$ 0.36
Weighted average shares outstanding - diluted	35,882	35,879	36,045	35,590	35,696	35,728	35,775	35,263	35,849	35,617	34,615