CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (4,075,574)	$ (11,044,104)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	135,258	173,524
Stock-based compensation expense	481,311	931,525
Fair value adjustment on warrant liabilities	(453,412)	32,119
Amortization of loan cost and discount	448,125	715,786
Changes in assets and liabilities:
Receivables	1,182,018	81,574
Prepaid expenses and other current assets	1,356,398	789,203
Accounts payable	(650,834)	121,126
Accrued expenses and other current liabilities	71,119	(39,707)
Net cash used in operating activities	(1,505,591)	(8,238,954)
Cash flows from investing activities:
Purchases of equipment and furnishings	0	(103,051)
Net cash used in investing activities	0	(103,051)
Cash flows from financing activities:
Payment of principal on term loan	(1,040,771)	(614,165)
Net cash used in financing activities	(1,040,771)	(614,165)
Net decrease in cash and cash equivalents	(2,546,362)	(8,956,170)
Cash and cash equivalents at beginning of period	37,643,404	56,959,485
Cash and cash equivalents at end of period	35,097,042	48,003,315
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	252,552	609,944
Supplemental disclosure of non-cash investing activities:
Preferred stock conversion	0	7,400
Equipment and furnishings purchased on credit	$ 0	$ 14,710