Condensed Statements of Cash Flows - USD ($)
9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Cash flows from operating activities    
Net loss $ (18,144,237) $ (19,951,226)
Adjustments to reconcile net loss to net cash used in operating activities:    
Share-based compensation 2,278,000 3,859,000
Write-off of deferred offering costs 100,056 0
Accrued interest on convertible notes 314,721 175,578
Amortization of debt discount 713,709 2,060,000
Depreciation 16,104 14,417
Beneficial conversion feature 0 3,077,887
Change in fair value of derivative liability (511,000) 0
Change in fair value of warrant liability (141,700) 0
Extinguishment of derivative liability (370,000) 0
Loss on extinguishment of debt 1,049,166 0
Changes in operating assets and liabilities:    
Prepaid expenses and other assets (276,185) (363,738)
Accounts payable (708,219) (754,435)
Accrued expenses 1,036,898 (878,181)
Accrued interest (101,624) 0
Net cash used in operating activities (14,744,311) (12,760,698)
Cash flows from investing activities    
Purchase of property and equipment (9,475) (13,943)
Loan payments from related party 0 75,000
Net cash (used in) provided by investing activities (9,475) 61,057
Cash flows from financing activities    
Borrowings from convertible notes 5,000,000 3,345,000
Payments of convertible notes (6,745,833) (275,000)
Payments of debt issuance costs (57,000) (20,000)
Proceeds from the exercise of stock options 30,064 0
Proceeds from issuance of common stock and warrants 20,706,919 18,132,661
Payment of deferred offering costs (1,045,468) (1,655,079)
Proceeds from exercise of warrants 0 928,178
Net cash provided by financing activities 17,888,682 20,455,760
Net increase in cash and cash equivalents 3,134,896 7,756,119
Cash and cash equivalents as of beginning of period 5,728,900 355,563
Cash and cash equivalents as of end of period 8,863,796 8,111,682
Supplemental disclosure of cash flow information    
Cash paid during the period for interest 418,927 280,287
Supplemental disclosure of non-cash financing activities    
Conversion of convertible notes and accrued interest to common stock 0 9,229,819
Assumption of liabilities from reverse recapitalization transaction 0 978,674
Warrants issued to placement agents 0 913,000
Commissions payable in connection with exercise of warrants 0 87,152
Non-cash addition of derivative liability 1,281,000 0
Non-cash addition of deferred offering costs $ 151,137 $ 0