Condensed Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (6,195,907)	$ (6,761,911)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	846,042	756,138
Non-cash interest	20,724	30,348
Deferred rent expense		(6,374)
Change in operating assets and liabilities:
Prepaid expenses and other assets	333,952	214,845
Accounts payable and accrued expenses	75,062	227,700
Net cash used in operating activities	(4,920,127)	(5,539,254)
Financing activities
Proceeds from issuance of common stock, net	358,023	1,266,533
Net cash provided by financing activities	358,023	1,266,533
Net decrease in cash and cash equivalents	(4,562,104)	(4,272,721)
Cash and cash equivalents at beginning of period	8,691,155	14,155,809
Cash and cash equivalents at end of period	4,129,051	9,883,088
Supplemental disclosure of cash flow information
Interest paid	$ 125,813	104,500
Non-cash financing activities
Deferred financing costs paid in prior year		$ 137,812