Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Consolidated net loss	$ (31,680,918)	$ (19,533,679)
Adjustments to reconcile consolidated net loss to net cash used in operating activities:
Gain on settlement of notes payable	0	(95,427)
Noncash stock compensation expense	11,600,014	11,970,284
Noncash stock expense associated with in-licensing agreement	0	1,211,250
Depreciation	5,805	1,558
Amortization of premium on investment securities	205,409	66,943
Change in fair value of notes payable	20,170	94,685
Changes in assets and liabilities:
Increase in restricted cash	(2,098)	0
Increase in other current assets	(5,117,040)	(2,383,969)
Increase in accrued interest receivable	(104,797)	(47,513)
Increase in other assets	0	(13,244)
Increase (decrease) in accounts payable and accrued expenses	4,018,767	(3,002,113)
Decrease in interest payable	0	(94,590)
Decrease in deferred revenue	(76,191)	(76,191)
Net cash used in operating activities	(21,130,879)	(11,902,006)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of equipment	(20,280)	(3,165)
Investment in held-to-maturity long-term securities	(18,324,355)	(6,127,539)
Investment in held-to-maturity short-term securities	(16,746,270)	(3,090,469)
Proceeds from maturity of short-term securities	7,850,000	0
Net cash used in investing activities	(27,240,905)	(9,221,173)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from the exercise of warrants	992,644	1,602,060
Payment of notes payable	0	(677,778)
Proceeds from sale of common stock, net	51,984,879	16,791,408
Deferred financing costs paid	(19,437)	0
Net cash provided by financing activities	52,958,086	17,715,690
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	4,586,302	(3,407,489)
Cash and cash equivalents at beginning of period	55,713,784	40,485,466
CASH AND CASH EQUIVALENTS AT END OF PERIOD	60,300,086	37,077,977
NONCASH TRANSACTIONS
Accrued financing costs	47,797	0
Reclassification of deferred financing costs to additional paid-in capital	$ (48,771)	$ 0