CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues [Abstract]
Total revenues	$ 138,285	$ 111,813	$ 300,243	$ 211,949
Costs and expenses:
Cost of revenues	0	204,436	0	570,780
Research and development	2,830,340	1,952,767	5,478,939	3,836,605
Selling, general and administrative	1,527,904	2,150,871	3,003,026	4,655,848
Restructuring charges	0	243,335	0	243,335
Total operating expenses	4,358,244	4,551,409	8,481,965	9,306,568
Loss from operations	(4,219,959)	(4,439,596)	(8,181,722)	(9,094,619)
Interest income	69,761	36,202	134,504	57,973
Interest expense	0	(925)	0	(25,161)
Gain from change in fair value of derivative financial instruments—warrants	23,789	711,229	14,028	581,540
Gain on extinguishment of debt	0	17,974	0	17,974
Other income (expense), net	1,106	(71,839)	3,116	(70,839)
Net loss	(4,125,303)	(3,746,955)	(8,030,074)	(8,533,132)
Preferred stock dividend payable on Series A Convertible Preferred Stock	(6,060)	(6,060)	(12,120)	(12,120)
Net loss attributable to common stockholders	$ (4,131,363)	$ (6,522,548)	$ (8,310,463)	$ (11,314,785)
Net loss per common share - basic (in USD per share)	$ (0.79)	$ (5.27)	$ (1.78)	$ (11.27)
Net loss per common share - diluted (in USD per share)	$ (0.79)	$ (5.27)	$ (1.78)	$ (11.27)
Weighted-average shares outstanding — basic (in shares)	5,241,924	1,237,244	4,667,434	1,004,391
Weighted-average shares outstanding — diluted (in shares)	5,241,924	1,237,244	4,667,434	1,004,391
Royalties
Revenues [Abstract]
Royalties	$ 36,852	$ 52,423	$ 98,873	$ 101,478
Services and other
Revenues [Abstract]
Services and other	101,433	59,390	201,370	110,471
Series B Convertible Preferred Stock
Costs and expenses:
Deemed dividend recognized for beneficial conversion features of Convertible Preferred Stock issuance	0	(2,769,533)	0	(2,769,533)
Series C Convertible Preferred Stock
Costs and expenses:
Deemed dividend recognized for beneficial conversion features of Convertible Preferred Stock issuance	$ 0	$ 0	$ (268,269)	$ 0