Statements Of Stockholders' Equity (USD $)	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2011	$ 5,543	$ 356,779,007	$ (205,999)	$ (375,407,446)	$ (18,828,895)
Shares at Dec. 31, 2011	5,543,157
Issuance of common stock and warrants, value	2,415	10,409,260			10,411,675
Issuance of common stock and warrants, shares	2,415,339
Share-based compensation, value		2,293,731			2,293,731
Issuance of stock under purchase plan, value	10	73,543			73,553
Issuance of stock under purchase plan, shares	10,315
Grant of restricted shares, net of forfeitures, value	20	(20)
Grant of restricted shares, net of forfeitures, shares	19,885
Restricted stock vestings, value	31	(31)
Restricted stock vestings, shares	29,919
Reclassification of warrants to liability		(3,501,863)			(3,501,863)
Net Loss				(9,238,427)	(9,238,427)
Balance at Dec. 31, 2012	8,019	366,053,627	(205,999)	(384,645,873)	(18,790,226)
Shares at Dec. 31, 2012	8,018,615
Issuance of common stock and warrants, value	7,743	64,586,770			64,594,513
Issuance of common stock and warrants, shares	7,742,717
Share-based compensation, value		1,050,260			1,050,260
Rights offering, value	3,400	10,197,647			10,201,047
Rights offering, shares	3,400,349
Grant of restricted shares, net of forfeitures, value	(62)	62
Grant of restricted shares, net of forfeitures, shares	(61,910)
Restricted stock vestings, value	211	(211)
Restricted stock vestings, shares	211,619
Net Loss				(68,757,589)	(68,757,589)
Balance at Dec. 31, 2013	19,311	441,888,155	(205,999)	(453,403,462)	(11,701,995)
Shares at Dec. 31, 2013	19,311,390
Issuance of common stock and warrants, value	879	2,852,794			2,853,673
Issuance of common stock and warrants, shares	878,077
Share-based compensation, value		1,501,045			1,501,045
Grant of restricted shares, net of forfeitures, shares	259
Restricted stock vestings, value	291	(291)
Restricted stock vestings, shares	291,148
Net Loss				(5,202,441)	(5,202,441)
Balance at Dec. 31, 2014	$ 20,481	$ 446,241,703	$ (205,999)	$ (458,605,903)	$ (12,549,718)
Shares at Dec. 31, 2014	20,480,874