Condensed Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (33,517,735)	$ (25,674,702)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	3,644,405	3,066,228
Stock-based 401K company common match	123,561	121,620
Depreciation expense	90,836	87,209
Impairment of machinery and equipment	2,672,581	0
Amortization of debt discount	1,039	22,012
Amortization of debt issuance costs	125,355	54,204
Non-cash interest expense	405,278	184,068
Changes in assets and liabilities:
Prepaid expenses and other assets	556,401	317,643
Accounts payable	(2,645,929)	824,032
Accrued expenses	602,322	940,303
Restructuring reserve	6,121,781	0
Net cash used in operating activities	(21,820,105)	(20,057,383)
Cash flows from investing activities:
Purchases of property and equipment	0	(105,662)
Net cash used in investing activities	0	(105,662)
Cash flows from financing activities:
Proceeds from issuance of debt	0	5,000,000
Proceeds from exercise of stock options	721,195	91,982
Proceeds from exercise of warrants	0	3,745
Payments for debt back-end fees	(990,000)	0
Repayment of debt	(20,000,000)	0
Proceeds from issuance of common stock, net of issuance costs	0	17,382,943
Net cash (used in) provided by financing activities	(20,268,805)	22,478,670
Net (decrease) increase in cash	(42,088,910)	2,315,625
Cash and cash equivalents at beginning of period	88,067,647	106,398,919
Cash and cash equivalents at end of period	45,978,737	108,714,544
Cash paid for:
Interest	1,051,167	705,313
Supplemental cash flow information:
Accrued capital expenditures included in accrued expenses and accounts payable	$ 0	$ 55,089