Condensed Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net loss	$ (5,805,448)	$ (11,921,069)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,161,266	1,404,926
Change in fair value of warrant liability	(433,392)	3,354,973
Change in operating assets and liabilities:
Prepaid expenses and other assets	(187,911)	(59,020)
Accounts payable and accrued expenses	(464,161)	1,236,986
Net cash used in operating activities	(5,729,646)	(5,983,204)
Financing activities
Proceeds from issuance of common stock, net	4,618,297	7,389,101
Net cash provided by financing activities	4,618,297	7,389,101
Net increase (decrease) in cash and cash equivalents	(1,111,349)	1,405,897
Cash and cash equivalents at beginning of period	7,679,267	9,007,071
Cash and cash equivalents at end of period	6,567,918	10,412,968
Non-cash financing activities
Reclassification of warrant liability to equity due to exercise of warrants		$ 1,399,091
Reclassification of warrant liability to equity due to amendment of warrants	$ 3,267,885