Condensed Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Condensed Statements of Operations and Comprehensive Loss
License income		$ 17,763,000		$ 19,687,000
Sublicense expense		1,760,000		1,936,000
Gross margin		16,003,000		17,751,000
Operating expenses:
Research and development	7,767,000	8,399,000	17,801,000	14,884,000
General and administrative	3,973,000	2,469,000	7,698,000	4,661,000
Total operating expenses	11,740,000	10,868,000	25,499,000	19,545,000
(Loss) income from operations	(11,740,000)	5,135,000	(25,499,000)	(1,794,000)
Interest income	35,000		63,000
Interest expense	(553,000)	(52,000)	(948,000)	(104,000)
Warrant and other income (expense), net		(577,000)		(476,000)
Net (loss) income	(12,258,000)	4,506,000	(26,384,000)	(2,374,000)
Other comprehensive (loss) income:
Unrealized loss on marketable securities	(23,000)		(31,000)
Comprehensive (loss) income	$ (12,281,000)	$ 4,506,000	$ (26,415,000)	$ (2,374,000)
Per share information:
Net (loss) income, basic and diluted (in dollars per share)	$ (0.67)	$ 0.35	$ (1.44)	$ (0.18)
Basic and diluted weighted average shares outstanding (in shares)	18,423,000	12,955,000	18,379,000	12,945,000