Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Product revenue	$ 917	$ 750	$ 2,136	$ 2,279
Contract revenue	73	545	355	746
Development revenue	880	0	1,180	0
Total revenue	1,870	1,295	3,671	3,025
Cost of product revenue	837	(281)	1,501	3,894
Cost of contract revenue	26	248	163	403
Total cost of revenue	863	(33)	1,664	4,297
Gross margin	1,007	1,328	2,007	(1,272)
Research and development expense	2,339	3,227	4,591	7,167
Sales, marketing, general and administrative expense	2,101	3,064	4,504	6,352
Gain on disposal of fixed assets	0	(1)	(2)	(1)
Total operating expenses	4,440	6,290	9,093	13,518
Loss from operations	(3,433)	(4,962)	(7,086)	(14,790)
Other income (expense)	(3)	(9)	(4)	16
Net loss	$ (3,436)	$ (4,971)	$ (7,090)	$ (14,774)
Net loss per share - basic and diluted	$ (0.13)	$ (0.26)	$ (0.27)	$ (0.82)
Weighted-average shares outstanding - basic and diluted	26,493	19,167	25,870	18,097