STATEMENTS OF STOCKHOLDERS' DEFICIT - 12 months ended Dec. 31, 2016 - USD ($)	Total	Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2015	$ (2,461,400)	$ 0	$ 172,889	$ 126,354,036	$ (128,988,325)
Balance (in shares) at Dec. 31, 2015		0	172,887,221
Net loss	(7,414,099)	$ 0	$ 0	0	(7,414,099)
Private placement of common stock, net of offering costs of $62,849	5,529,651	$ 0	$ 56,263	5,473,388	0
Private placement of common stock, net of offering costs of $62,849 (in shares)		0	56,262,571
Horizon warrant	503,667	$ 0	$ 0	503,667	0
Danforth warrant	8,885	0	0	8,885	0
Exercise of employee stock options	$ 0	$ 1	$ 0	67	0
Exercise of employee stock options (in shares)	1,316	1,316	66
Employee stock purchase plan	$ 15,991	$ 0	$ 230	15,761	0
Employee stock purchase plan (in shares)		0	229,951
Stock-based compensation expense	971,688	$ 0	$ 0	971,688	0
Balance at Dec. 31, 2016	$ (2,845,550)	$ 0	$ 229,383	$ 133,327,491	$ (136,402,424)
Balance (in shares) at Dec. 31, 2016		0	229,381,059