CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
License fees and royalties	$ 112	$ 130	$ 877	$ 1,384
Operating expenses:
Research and development	4,807	12,777	12,728	27,884
Restructuring charges	838		916
General and administrative	3,432	5,832	8,183	10,897
Total operating expenses	9,077	18,609	21,827	38,781
Loss from operations	(8,965)	(18,479)	(20,950)	(37,397)
Unrealized (loss) gain on derivatives	(24)	8	1	34
Interest and other income	56	165	137	341
Interest and other expense	(14)	(20)	(32)	(43)
Net loss	$ (8,947)	$ (18,326)	$ (20,844)	$ (37,065)
Basic and diluted net loss per share (in dollars per share)	$ (0.07)	$ (0.14)	$ (0.16)	$ (0.29)
Shares used in computing basic and diluted net loss per share (in shares)	128,162,993	126,891,909	128,072,962	126,632,377