Statements of Comprehensive Loss (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Product revenues	$ 95	$ 156
Operating expenses:
Research and development	3,636	3,523	5,291
General and administrative	4,739	4,690	5,375
Restructuring (Note 4)		15	1,226
Total operating expenses	8,375	8,228	11,892
Loss from operations	(8,280)	(8,072)	(11,892)
Change in fair value of warrants		6	2,222
Investment income	4	12	7
Other (expense) income, net	(1)	(25)	10
Net loss and comprehensive loss	(8,277)	(8,079)	(9,653)
Non-cash deemed dividend to preferred stock	(4,799)
Net loss attributable to common stock	$ (13,076)	$ (8,079)	$ (9,653)
Basic and diluted net loss per share attributable to common stock	$ (4.67)	$ (5.48)	$ (10.37)
Weighted-average number of common shares outstanding	2,803	1,473	931