Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		134 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013
Revenue:
Research revenue		$ 6,114	$ 57,493
Collaboration and milestone revenue		1,660	64,382
Total revenue		7,774	121,875
Operating Expenses:
Research and development	11,989	14,004	327,882
General and administrative	4,823	4,095	137,436
Restructuring charges			1,522
Impairment of leasehold improvements			1,030
Depreciation and amortization	439	420	12,207
In-process research and development			418
Total operating expenses	17,251	18,519	480,495
Loss from operations	(17,251)	(10,745)	(358,620)
Other income (expenses):
Interest income	65	27	14,454
Interest expense	(10)	(43)	(2,432)
Change in fair value of warrant liability	(262)	(2,376)	1,291
Other income			252
Loss before tax benefit	(17,458)	(13,137)	(345,055)
Income tax benefit			8,708
Net loss	(17,458)	(13,137)	(336,347)
Deemed dividend			(19,424)
Preferred stock accretion			(802)
Net loss attributable to common stockholders	$ (17,458)	$ (13,137)	$ (356,573)
Net loss attributable to common stockholders per common share - basic and diluted (in dollars per share)	$ (0.35)	$ (0.35)
Weighted-average common shares outstanding - basic and diluted (in shares)	49,621,188	37,887,520