Statements Of Convertible Preferred Stock And Stockholders' Equity - USD ($)	Common Stock [Member]	Convertible Preferred Stock [Member]	Additional Paid-In Capital [Member] Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Common Stock [Member]	Total
Balance, Amount at Dec. 31, 2015	$ 21,551			$ 448,517,472	$ (205,999)	$ (465,958,678)		$ (17,625,654)
Balance, Shares at Dec. 31, 2015	21,551,173
Issuance of common stock			$ (1,464)				$ (1,464)
Issuance of stock, Amount		$ 5,986,081
Issuance of stock, Shares		24,000
Share-based compensation				1,365,121				1,365,121
Restricted stock vestings, Amount	$ 318			(318)
Restricted stock vestings, Shares	317,962
Net loss						(5,286,720)		(5,286,720)
Employee stock purchase plan, Amount	$ 39			33,145				33,184
Employee stock purchase plan, Shares	39,008
Beneficial conversion feature of Convertible Preferred Stock		$ (6,145,402)		6,145,402				6,145,402
Deemed dividend related to beneficial conversion feature of Convertible Preferred Stock		6,145,402		(6,145,402)				(6,145,402)
Conversion of Convertible Preferred Stock, Amount	$ 156	$ (25,606)		25,450				25,606
Conversion of Convertible Preferred Stock, Shares	155,439	(100)
Balance, Amount at Dec. 31, 2016	$ 22,064	$ 5,960,475		449,939,406	(205,999)	(471,245,398)		(21,489,927)
Balance, Shares at Dec. 31, 2016	22,063,582	23,900
Share-based compensation				768,682				768,682
Restricted stock vestings, Amount	$ 675			(552)				123
Restricted stock vestings, Shares	675,473
Net loss						(5,887,410)		(5,887,410)
Employee stock purchase plan, Amount	$ 67			40,867				40,934
Employee stock purchase plan, Shares	66,676
Deemed dividend related to beneficial conversion feature of Convertible Preferred Stock								(6,100,000)
Balance, Amount at Dec. 31, 2017	$ 22,806	$ 5,960,475		$ 450,748,403	$ (205,999)	$ (477,132,808)		$ (26,567,598)
Balance, Shares at Dec. 31, 2017	22,805,731	23,900