Condensed Statements of Operations and Comprehensive Loss (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Condensed Statements of Operations and Comprehensive Loss [Abstract]
Alliance revenue	$ 7	$ 9
Operating expenses:
Research and development	2,328	3,813
General and administrative	1,527	1,689
Total operating expenses	3,855	5,502
Loss from operations	(3,848)	(5,493)
Other income (expense):
Increase in fair value of warrant liability		(1,321)
Investment income, net	2	4
Foreign currency exchange gain (loss)	39	(76)
Net loss	(3,807)	(6,886)
Preferred stock dividends	279	160
Net loss applicable to common stockholders	(4,086)	(7,046)
Net loss per common share applicable to common stockholders (Note 10):
Basic	$ (0.15)	$ (0.25)
Diluted	$ (0.15)	$ (0.25)
Shares used in computing net loss per common share applicable to common stockholders:
Basic	27,644	27,637
Diluted	27,644	27,637
Net loss	(3,807)	(6,886)
Other comprehensive income
Comprehensive loss	$ (3,807)	$ (6,886)