STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)	Total	Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2013	$ 5,253,222	$ 0	$ 122,449	$ 119,885,371	$ (114,754,598)
Balance (in shares) at Dec. 31, 2013		0	122,448,707
Net loss	(6,335,714)	$ 0	$ 0	0	(6,335,714)
Private placement of preferred stock	4,806,874	$ 0	$ 50,100	4,756,774	0
Private placement of preferred stock (in shares)		0	50,099,700
Horizon warrant	261,386	$ 0	$ 0	261,386
Employee stock purchase plan	32,154	$ 0	$ 137	32,017	0
Employee stock purchase plan (in shares)		0	134,935
Stock-based compensation expense	498,935	$ 0	$ 0	498,935	0
Balance at Dec. 31, 2014	4,516,857	$ 0	$ 172,686	125,434,483	(121,090,312)
Balance (in shares) at Dec. 31, 2014		0	172,683,342
Net loss	(7,898,013)	$ 0	$ 0	0	(7,898,013)
Private placement of preferred stock	(8,095)	0	0	(8,095)
Horizon warrant	14,810	0	0	14,810	0
Employee stock purchase plan	20,954	$ 0	$ 203	20,751	0
Employee stock purchase plan (in shares)		0	203,879
Stock-based compensation expense	892,087	$ 0	$ 0	892,087	0
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