CONDENSED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net loss	$ (8,030,074)	$ (8,533,132)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on disposal of assets	0	198,099
Impairment loss	0	187,500
Depreciation and amortization	87,219	483,495
Stock-based compensation expense	348,901	1,627,431
Gain on extinguishment of debt	0	(17,974)
Deferred rent	0	(163,847)
Change in fair value of derivative financial instruments—warrants	(14,028)	(581,540)
Release of clinical trial funding commitment	310,766	0
Changes in operating assets and liabilities:
Other assets	(32,464)	(199,743)
Accounts receivable and unbilled receivable	45,474	62,935
Prepaid expenses	163,950	191,321
Operating lease right-of-use assets	309,713	0
Accounts payable and accrued expenses	387,046	638,701
Operating lease liabilities	(379,662)	0
Net cash used in operating activities	(6,803,159)	(6,106,754)
Investing activities:
Capital expenditures	(5,274)	(5,100)
Purchases of short-term investments	0	(31,500)
Net cash used in investing activities	(5,274)	(36,600)
Financing activities:
Proceeds from sales of common stock and warrants, net of expenses of $97,260 and $1,336,123, respectively	2,902,740	11,779,525
Proceeds from sales of Series B Convertible Preferred Stock, net of expenses of $497,617	0	4,386,762
Costs related to the clinical trial funding commitment	(40,000)	0
Proceeds from exercise of warrants	3,283,830	1,612,667
Payment upon debt extinguishment	0	(175,381)
Repayments of equipment line of credit	0	(1,200,033)
Net cash provided by financing activities	6,146,570	16,403,540
Net change in cash and cash equivalents	(661,863)	10,260,186
Cash and cash equivalents—Beginning of period	11,453,133	8,225,764
Cash and cash equivalents—End of period	10,791,270	18,485,950
Supplementary disclosure of cash flow activity:
Cash paid for taxes	800	800
Cash paid for interest	0	22,482
Supplemental disclosure of non-cash investing and financing activities:
Preferred stock dividend payable on Series A Convertible Preferred Stock	12,120	12,120
Common stock, preferred stock and warrants issued in connection with clinical trial funding commitment	1,675,000	0
Series B Convertible Preferred Stock
Supplemental disclosure of non-cash investing and financing activities:
Deemed dividend recognized for beneficial conversion features of Series C Convertible Preferred Stock issuance	0	2,769,533
Common stock issued upon conversion of Preferred Stock	0	321
Series C Convertible Preferred Stock
Supplemental disclosure of non-cash investing and financing activities:
Deemed dividend recognized for beneficial conversion features of Series C Convertible Preferred Stock issuance	268,269	0
Common stock issued upon conversion of Preferred Stock	$ 33	$ 0