Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (18,699,450)	$ (12,090,287)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,759,753	2,187,102
Amortization of debt discount - non-cash interest expense	27,314	35,829
Net amortization of premium on debt securities available for sale	266,106
Depreciation	35,792	18,778
Change in assets and liabilities:
Prepaid expenses and other current assets	278,870	(264,984)
Accounts payable	(575,719)	509,866
Accrued expenses	759,822	291,943
Net cash used in operating activities	(15,147,512)	(9,311,753)
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions of property and equipment	(11,810)	(86,119)
Purchases of marketable securities	(16,048,424)	(12,950,137)
Sales of marketable securities	15,835,000
Net cash used in investing activities	(225,234)	(13,036,256)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock and exercise of options	12,738,941	28,505,807
Deferred offering costs paid in cash		(36,236)
Net cash provided by financing activities	12,738,941	28,469,571
NET (DECREASE)/INCREASE IN CASH	(2,633,805)	6,121,562
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	14,648,866	8,527,304
CASH AND CASH EQUIVALENTS, END OF PERIOD	12,015,061	14,648,866
Cash paid during the period for:
Interest	$ 78,128	$ 74,299