Statements of Operations and Comprehensive Loss (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Statements of Operations and Comprehensive Loss
License income	$ 19,687,000		$ 12,985,000		$ 4,488,000
Sublicense expense	1,936,000		1,188,000		411,000
Gross margin	17,751,000		11,797,000		4,077,000
Operating expenses:
Research and development	43,184,000		15,766,000		14,842,000
General and administrative	10,505,000		6,879,000		6,785,000
Total operating expenses	53,689,000		22,645,000		21,627,000
Loss from operations	(35,938,000)		(10,848,000)		(17,550,000)
Warrant and other interest (expense) income, net	(861,000)		(304,000)		589,000
Other income					930,000
Net loss	(36,799,000)		(11,152,000)		(16,031,000)
Other comprehensive income (loss):
Unrealized gain on marketable securities					4,000
Comprehensive loss	$ (36,799,000)		$ (11,152,000)		$ (16,027,000)
Per share information:
Net loss, basic and diluted (restated) (in dollars per share)	$ (7.47)		$ (7.98)		$ (11.64)
Basic and diluted weighted average shares outstanding (restated) (in shares)	4,924,000	[1]	1,398,000	[1]	1,377,000	[1]

[1] Since the numerator was a loss for each of the periods presented, the dilutive effects of stock options, warrants and redeemable convertible preferred stock were not included in the calculation of diluted net loss per share as the effect was anti-dilutive.