Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Product revenue	$ 3,617	$ 2,078	$ 10,302	$ 5,001
Royalty revenue	331	309	1,482	777
Contract revenue	52	11	72	1,564
Total revenue	4,000	2,398	11,856	7,342
Cost of product revenue	2,767	1,810	7,942	4,921
Cost of contract revenue	26	3	32	792
Total cost of revenue	2,793	1,813	7,974	5,713
Gross profit	1,207	585	3,882	1,629
Research and development expense	3,053	2,231	8,529	6,140
Sales, marketing, general and administrative expense	2,231	1,873	6,470	5,740
Total operating expenses	5,284	4,104	14,999	11,880
Loss from operations	(4,077)	(3,519)	(11,117)	(10,251)
Other income, net	7	6	15	7
Net loss	$ (4,070)	$ (3,513)	$ (11,102)	$ (10,244)
Net loss per share - basic and diluted	$ (0.08)	$ (0.07)	$ (0.22)	$ (0.22)
Weighted-average shares outstanding - basic and diluted	52,111	47,216	50,421	46,292