CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:
License fees and royalties	$ 181	$ 636	$ 1,058	$ 2,020
Operating expenses:
Research and development	5,338	11,684	18,066	39,568
Restructuring charges	116		1,032
General and administrative	3,460	4,829	11,643	15,726
Total operating expenses	8,914	16,513	30,741	55,294
Loss from operations	(8,733)	(15,877)	(29,683)	(53,274)
Unrealized loss on derivatives	(208)	(44)	(207)	(10)
Interest and other income	699	140	836	481
Interest and other expense	(12)	(172)	(44)	(215)
Net loss	$ (8,254)	$ (15,953)	$ (29,098)	$ (53,018)
Basic and diluted net loss per share (in dollars per share)	$ (0.06)	$ (0.13)	$ (0.23)	$ (0.42)
Shares used in computing basic and diluted net loss per share (in shares)	128,293,074	127,236,993	128,146,333	126,833,916