Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Product revenue	$ 6,782	$ 4,338
Contract revenue	1,583	1,279
Total revenue	8,365	5,617
Cost of product revenue	6,085	11,640
Cost of contract revenue	839	1,425
Total cost of revenue	6,924	13,065
Gross margin	1,441	(7,448)
Research and development expense	13,135	15,279
Sales, marketing, general and administrative expense	11,252	13,314
Gain on disposal of fixed assets	(79)	(11)
Total operating expenses	24,308	28,582
Loss from operations	(22,867)	(36,030)
Other income, net	174	222
Net loss	$ (22,693)	$ (35,808)
Net loss per share - basic and diluted	$ (1.05)	$ (2.57)
Weighted-average shares outstanding - basic and diluted	21,595	13,919