Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (13,848,662)	$ (14,577,735)
Adjustments to reconcile net loss to net cash used in operating activities:
Noncash stock compensation expense	1,698,965	5,357,028
Depreciation	6,380	2,419
Amortization of premium on investment securities	128,329	80,597
Deferred rent	389,554	0
Change in fair value of notes payable	(58,632)	(2,984)
Changes in assets and liabilities:
Increase in restricted cash	(1,008)	(1,060)
Increase in other current assets	(2,250,490)	(4,159,055)
Increase in prepaid rent	(1,151,163)	0
Decrease (increase) in accrued interest receivable	21,915	(4,194)
Decrease in other assets	5,341	25,913
(Decrease) increase in accounts payable and accrued expenses	(1,575,974)	4,434,813
Decrease in deferred revenue	(38,096)	(38,095)
Net cash used in operating activities	(16,673,541)	(8,882,353)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(282,261)	(6,883)
Investment in held-to-maturity securities	(10,641,270)	0
Proceeds from maturity of short-term securities	9,000,000	3,850,000
Net cash (used in) provided by investing activities	(1,923,531)	3,843,117
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from the exercise of warrants	22,163	408,286
Proceeds from sale of common stock, net	0	34,941,049
Financing costs	(8,000)	(19,438)
Net cash provided by financing activities	14,163	35,329,897
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(18,582,909)	30,290,661
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	55,061,329	55,713,784
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 36,478,420	$ 86,004,445