Condensed Statements of Comprehensive Loss (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Statements of Comprehensive Loss [Abstract]
Alliance revenue	$ 3	$ 4	$ 40	$ 45
Operating expenses:
Research and development	3,278	3,574	10,595	12,269
General and administrative	1,477	1,948	5,014	6,400
Total operating expenses	4,755	5,522	15,609	18,669
Loss from operations	(4,752)	(5,518)	(15,569)	(18,624)
Other income (expense):
Decrease in fair value of warrant liability	109		106
Investment income, net	2	2	8	28
Foreign currency exchange (loss) gain	(28)	27	13	(20)
Net loss	(4,669)	(5,489)	(15,442)	(18,616)
Preferred stock dividends	160		480
Net loss applicable to common stockholders	(4,829)	(5,489)	(15,922)	(18,616)
Net loss per common share applicable to common stockholders (Note 10):
Basic	$ (0.17)	$ (0.20)	$ (0.58)	$ (0.67)
Diluted	$ (0.17)	$ (0.20)	$ (0.58)	$ (0.67)
Shares used in computing net loss per common share applicable to common stockholders:
Basic	27,640	27,632	27,639	27,618
Diluted	27,640	27,632	27,639	27,618
Net loss	(4,669)	(5,489)	(15,442)	(18,616)
Other comprehensive loss:
Decrease in unrealized gain on available-for-sale securities				(13)
Other comprehensive loss				(13)
Comprehensive loss	$ (4,669)	$ (5,489)	$ (15,442)	$ (18,629)