Condensed Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities
Net loss	$ (3,225,409)	$ (3,520,748)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	418,912	371,600
Non-cash interest	10,362	15,174
Deferred rent expense		(3,298)
Change in operating assets and liabilities:
Prepaid expenses and other assets	68,555	73,333
Accounts payable and accrued expenses	37,379	68,870
Net cash used in operating activities	(2,690,201)	(2,995,069)
Financing activities
Proceeds from issuance of common stock, net	98,744	531,620
Net cash provided by financing activities	98,744	531,620
Net decrease in cash and cash equivalents	(2,591,457)	(2,463,449)
Cash and cash equivalents at beginning of period	8,691,155	14,155,809
Cash and cash equivalents at end of period	6,099,698	11,692,360
Supplemental disclosure of cash flow information
Interest paid	$ 62,563	41,250
Non-cash financing activities
Deferred financing costs paid in prior year		$ 137,812