Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended			263 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Revenue	$ 35	$ 50	$ 93	$ 3,166
Operating expenses:
Research and development	101,522	99,959	112,279	1,467,573
General and administrative	45,473	40,630	40,312	425,704
In-process research and development costs				19,726
Goodwill impairment				151,428
Total operating expenses	146,995	140,589	152,591	2,064,431
Loss from operations	(146,960)	(140,539)	(152,498)	(2,061,265)
Other income (expense)	(1,191)	1,541	(725)	(2,267)
Interest expense on note payable to related party	(10,491)	(10,883)	(10,249)	(38,825)
Interest expense on senior convertible notes	(11,139)	(10,941)	(7,128)	(39,933)
Interest income	7	18	40	36,996
Loss before benefit for income taxes	(169,774)	(160,804)	(170,560)	(2,105,294)
Income tax benefit	(408)			(382)
Net loss	(169,366)	(160,804)	(170,560)	(2,104,912)
Deemed dividend related to beneficial conversion feature of convertible preferred stock				(22,260)
Accretion on redeemable preferred stock				(952)
Net loss applicable to common stockholders	$ (169,366)	$ (160,804)	$ (170,560)	$ (2,128,124)
Net loss per share applicable to common stockholders - basic and diluted	$ (0.94)	$ (1.32)	$ (1.50)
Shares used to compute basic and diluted net loss per share applicable to common stockholders	180,855	121,817	113,672