Summary of Significant Accounting Policies (Details 3) (USD $) In Thousands, except 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
Revenue Recognition
Period for which company is having option of accepting returns from customers									60 days
Deferred product revenue	$ 537				$ 786				$ 537	$ 786
Deferred cost of product revenue	476				219				476	219
Basic and Diluted Net Loss per Share
Difference in basic and dilutive loss per share (in dollars per share)									$ 0.00
Numerator:
Net income (loss)	$ (8,626)	$ (7,251)	$ (7,866)	$ (6,763)	$ (9,517)	$ (7,745)	$ (7,948)	$ 28,840	$ (30,506)	$ 3,630	$ (38,785)
Denominator:
Weighted average number of common shares outstanding									34,471,301	34,217,298	31,257,376
Effect of dilutive securities:
Stock options (in shares)										62,481
Dilutive potential common shares										62,481
Shares used in calculating diluted earnings per share									34,471,301	34,279,779	31,257,376
Antidilutive securities
Antidilutive common stock excluded from the calculation of dilutive shares									6,205,515	5,583,128	3,862,771
Options
Antidilutive securities
Antidilutive common stock excluded from the calculation of dilutive shares									6,201,429	5,579,042	3,858,685
Warrants
Antidilutive securities
Antidilutive common stock excluded from the calculation of dilutive shares									4,086	4,086	4,086