Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Licensing revenue	$ 500,000	$ 500,000	$ 500,000
Operating expenses:
Research and development	14,659,941	14,969,382	9,364,228
General and administrative	6,686,852	8,860,549	6,547,257
Acquisition costs		1,385,263
Total operating expenses	21,346,793	25,215,194	15,911,485
Loss from operations	(20,846,793)	(24,715,194)	(15,411,485)
Other income (expense):
(Loss) gain from valuation of earn-out milestone liability	(257,702)	213,949
(Loss) gain from valuation of common stock warrant liability	(61,246)	204,279	8,090,636
Investment income (loss), net	63,588	77,194	(12,744)
Interest expense	(1,357,182)	(1,326,438)	(915,235)
Other (expense) income	(1,749)	51,937	(2,530)
Total other (expense) income	(1,614,291)	(779,079)	7,160,127
Net loss	(22,461,084)	(25,494,273)	(8,251,358)
Non-cash deemed dividend from beneficial conversion feature on convertible preferred stock			(4,601,410)
Net loss attributable to common shareholders	$ (22,461,084)	$ (25,494,273)	$ (12,852,768)
Net loss per common share – basic and diluted (in Dollars per share)	$ (1.03)	$ (1.38)	$ (0.95)
Weighted average common shares outstanding – basic and diluted (in Shares)	21,813,228	18,472,399	13,540,566