Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Product revenue	$ 12,849	$ 6,452	$ 352
Royalty revenue	1,803	1,165	40
Contract revenue	109	1,571	1,402
Development revenue	0	0	1,691
Total revenue	14,761	9,188	3,485
Cost of product revenue	10,320	6,384	228
Cost of contract revenue	54	796	816
Total cost of revenue	10,374	7,180	1,044
Gross profit	4,387	2,008	2,441
Research and development expense	12,134	8,680	9,067
Sales, marketing, general and administrative expense	8,743	7,879	7,005
Gain on sale of previously reserved inventory	(32)	(1)	(463)
Total operating expenses	20,845	16,558	15,609
Loss from operations	(16,458)	(14,550)	(13,168)
Loss on warrant exchange	0	0	(4,967)
Other income (expense), net	(14)	8	15
Net loss	$ (16,472)	$ (14,542)	$ (18,120)
Net loss per share - basic and diluted	$ (0.32)	$ (0.31)	$ (0.44)
Weighted-average shares outstanding - basic and diluted	51,958	46,540	41,599