Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues:
Product sales	$ 42	$ 0	$ 70	$ 0
Grant revenue	1,051	182	1,054	254
Total revenues	1,093	182	1,124	254
Expenses:
Cost of product sales	731	0	1,512	0
Research and development	6,858	6,863	12,448	15,335
Selling, general and administrative	4,446	4,129	8,869	8,349
Total expenses	12,035	10,992	22,829	23,684
Operating loss	(10,942)	(10,810)	(21,705)	(23,430)
Change in fair value of common stock warrant liability	1,448	2,525	1,826	2,686
Other income / (expense):
Interest and other income	2	1	4	1
Interest and other expense	(1,131)	(343)	(2,224)	(520)
Other income / (expense), net	(1,129)	(342)	(2,220)	(519)
Net loss	$ (10,623)	$ (8,627)	$ (22,099)	$ (21,263)
Net loss per common share
Basic (in dollars per share)	$ (0.12)	$ (0.18)	$ (0.26)	$ (0.46)
Diluted (in dollars per share)	$ (0.14)	$ (0.22)	$ (0.28)	$ (0.50)
Weighted-average number of common shares outstanding
Basic (in shares)	85,061	49,135	84,766	46,411
Diluted (in shares)	85,882	49,866	86,111	47,773