Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues:
Collaboration agreements	$ 7,568	$ 4,083
Research grants	548	540
Total revenues	8,116	4,623
Operating expenses:
Research and development	12,033	8,220
General and administrative	3,644	3,308
Change in fair value of contingent liability	50
Total operating expenses	15,727	11,528
Loss from operations	(7,611)	(6,905)
Interest and other income, net	39	20
Net loss	$ (7,572)	$ (6,885)
Basic and diluted net loss per share	$ (0.12)	$ (0.13)
Shares used in computing basic and diluted net loss per share	63,199	53,377