Condensed Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net loss	$ (9,497,311)	$ (10,327,878)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,127,813	792,481
Non-cash interest	45,521	54,076
Deferred rent expense	(9,227)	7,884
Change in operating assets and liabilities:
Prepaid expenses and other assets	(4,405)	(349,915)
Accounts payable and accrued expenses	294,244	843,153
Net cash used in operating activities	(8,043,365)	(8,980,199)
Financing activities
Payment on bank line of credit		(3,000,000)
Costs paid in connection with loan origination		(82,685)
Proceeds from issuance of common stock	4,626,373	42,875
Net cash provided by (used in) financing activities	4,626,373	(3,039,810)
Net increase (decrease) in cash and cash equivalents	(3,416,992)	(12,020,009)
Cash and cash equivalents at beginning of period	14,155,809	24,196,691
Cash and cash equivalents at end of period	10,738,817	12,176,682
Supplemental disclosure of cash flow information
Interest paid	$ 167,750	$ 58,790