Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Collaboration agreements	$ 781	$ 2,234	$ 2,876	$ 14,643
Research grants	1,076	709	2,695	1,473
Total revenues	1,857	2,943	5,571	16,116
Operating expenses:
Research and development	7,839	8,769	24,220	23,281
General and administrative	3,592	2,889	10,807	9,432
Total operating expenses	11,431	11,658	35,027	32,713
Loss from operations	(9,574)	(8,715)	(29,456)	(16,597)
Interest and other income, net	20	20	65	64
Net loss	$ (9,554)	$ (8,695)	$ (29,391)	$ (16,533)
Basic and diluted net loss per share	$ (0.18)	$ (0.19)	$ (0.59)	$ (0.37)
Shares used in computing basic and diluted net loss per share	52,464	45,201	49,850	45,131