Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Product	$ 82	$ 102	$ 482	$ 422
License	144	218	353	510
Contract research and government grants	363	755	1,763	1,716
Total revenues	589	1,075	2,598	2,648
Operating expenses:
Cost of product revenues	40	60	262	242
Research and development	1,749	2,255	5,241	6,673
Selling, general and administrative	2,415	2,687	8,410	8,882
Total operating expenses	4,204	5,002	13,913	15,797
Loss from operations	(3,615)	(3,927)	(11,315)	(13,149)
Interest expense	(43)	(331)	(747)	(985)
Other income, net	46	90	246	242
Loss on extinguishment of debt	(900)		(900)
Net loss before income taxes	(4,512)	(4,168)	(12,716)	(13,892)
Income tax provision	(13)	(7)	(31)	(24)
Net loss and net loss attributable to common stockholders	$ (4,525)	$ (4,175)	$ (12,747)	$ (13,916)
Net loss per share attributable to common stockholders:
Basic and diluted	$ (0.11)	$ (0.09)	$ (0.29)	$ (0.31)
Weighted-average number of shares used in per share calculations:
Basic and diluted	42,676,916	44,370,061	43,272,083	44,336,324
Other comprehensive income (loss), net of tax
Unrealized gains (loss) on available-for-sale securities	$ 8	$ (1)	$ 14	$ 108
Other comprehensive income (loss)	8	(1)	14	108
Comprehensive loss attributable to common stockholders	$ (4,517)	$ (4,176)	$ (12,733)	$ (13,808)