Statements of Operations (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Licensing revenue	$ 500,000		$ 2,000,000
Research and development	9,364,228	15,770,166	19,863,836
General and administrative	6,547,257	6,372,551	5,154,933
Total operating expenses	15,911,485	22,142,717	25,018,769
Loss from operations	(15,411,485)	(22,142,717)	(23,018,769)
Non-cash deemed dividend from beneficial conversion feature on convertible preferred stock	(4,601,410)
Net loss attributable to common shareholders	(12,852,768)	(26,568,382)	(23,222,678)
Net loss per common share – basic and diluted (in Dollars per share)	$ (0.95)	$ (3.44)	$ (5.00)
Weighted average common shares outstanding –basic and diluted (in Shares)	13,540,566	7,730,904	4,648,373
Gain (loss) from valuation of common stock warrant liability	8,090,636	(4,117,534)	81,733
Investment (loss) income, net	(12,744)	52,322	174,064
Interest expense	(915,235)	(359,413)	(501,855)
Other (expense) income	(2,530)	(1,040)	42,149
Total other income (expense)	7,160,127	(4,425,665)	(203,909)
Net Loss [Member]
Loss from operations	$ (8,251,358)	$ (26,568,382)	$ (23,222,678)