Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (55,781,277)	$ (20,478,210)
Adjustments to reconcile net loss to net cash used in operating activities:
Gain on settlement of note payable	(95,427)	0
Noncash stock compensation expense	21,105,292	5,203,148
Noncash stock expense associated with in-licensing agreements	5,350,094	0
Impairment of in-process research and development	0	2,797,600
Depreciation	3,931	1,127
Amortization of premium on investment securities	193,581	975
Change in fair value of notes payable	210,661	(2,414,569)
Changes in assets and liabilities, net of effects of acquisition:
Increase in restricted cash	(575,012)	0
(Increase) decrease in other current assets	(4,563,067)	229,258
Increase in accrued interest receivable	(58,347)	(27,169)
(Decrease) increase in accounts payable and accrued expenses	(603,377)	4,034,605
(Decrease) increase in interest payable	(94,590)	66,506
Decrease in deferred revenue	(152,381)	(152,381)
Net cash used in operating activities	(35,059,919)	(10,739,110)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of equipment	(18,570)	(5,681)
Investment in held-to-maturity long-term securities	0	(4,919,871)
Investment in held-to-maturity short-term securities	(18,336,719)	0
Net cash used in investing activities	(18,355,289)	(4,925,552)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the exercise of warrants	3,556,624	2,280,773
Proceeds from the exercise of options	202,400	0
Payment of notes payable	(677,778)	0
Proceeds from sale of common stock, net	65,614,260	37,648,280
Deferred financing costs paid	(51,980)	(85,121)
Purchase of treasury stock	0	(149,799)
Net cash provided by financing activities	68,643,526	39,694,133
NET INCREASE IN CASH AND CASH EQUIVALENTS	15,228,318	24,029,471
Cash and cash equivalents at beginning of year	40,485,466	16,455,995
CASH AND CASH EQUIVALENTS AT END OF YEAR	$ 55,713,784	$ 40,485,466