CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Revenues from collaborative agreements	$ 0	$ 150
License fees and royalties	1,254	1,355
Total revenues	1,254	1,505
Operating expenses:
Research and development	15,107	16,755
General and administrative	5,065	9,106
Total operating expenses	20,172	25,861
Loss from operations	(18,918)	(24,356)
Unrealized gain on fair value of derivatives	26	39
Interest and other income	176	296
Losses recognized under equity method investment	0	(335)
Interest and other expense	(23)	(33)
Net loss	$ (18,739)	$ (24,389)
Basic and diluted net loss per share (in dollars per share)	$ (0.15)	$ (0.20)
Shares used in computing basic and diluted net loss per share (in shares)	126,372,846	123,098,728