Consolidated Statements of Comprehensive Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Comprehensive Operations
License fees	$ 0	$ 1,002	$ 4
Other expanded access program income, net	0	3,415	6,917
Total revenues	0	4,417	6,921
Operating expenses:
Research and development	29,781	28,623	4,702
General and administrative	12,657	11,523	10,311
Impairment loss	0	25,990	0
Total operating expenses	42,438	66,136	15,013
Operating loss	(42,438)	(61,719)	(8,092)
Investment income	1,822	2,064	1,845
Interest expense	(763)	(10)	(109)
Gain on sale of asset, net	5	1	0
Loss before income taxes	(41,374)	(59,664)	(6,356)
Provision for income taxes	0	0	78
Net loss	(41,374)	(59,664)	(6,434)
Accretion of beneficial conversion charge	0	(9,175)	0
Net loss attributable to common stockholders	(41,374)	(68,839)	(6,434)
Basic and diluted net loss attributable to common stockholders per share (in dollars per share)	$ (1.56)	$ (2.95)	$ (0.49)
Weighted average basic and diluted common shares outstanding (in shares)	26,545	23,348	13,250
Net loss attributable to common stockholders	(41,374)	(68,839)	(6,434)
Comprehensive loss: [Abstract]
Unrealized gains on investments, net of taxes	0	450	993
Comprehensive loss attributable to common stockholders	$ (41,374)	$ (68,389)	$ (5,441)
Weighted average diluted common shares outstanding (in shares)	26,545,000	23,348,000	13,250,000