Statements of Stockholders' Equity (USD $)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning Balance at Dec. 31, 2009	$ 30,315,830	$ 22,354	$ 109,513,582	$ (79,220,106)
Beginning Balance, Shares at Dec. 31, 2009		22,354,317
Exercise of options	33,088	13	33,075
Exercise of options, Shares	29,206	12,944
Cashless exercise of options		16	(16)
Cashless exercise of options, Shares		16,262
Exercise of warrants	1,691,634	240	1,691,394
Exercise of warrants, Shares		239,723
Cashless exercise of warrants		33	(33)
Cashless exercise of warrants, Shares		32,548
Issuance of shares of common stock in connection with a public offering (net of expenses)	15,233,671	2,200	15,231,471
Issuance of shares of common stock in connection with a public offering (net of expenses), Shares		2,200,000
Issuance of shares of common stock in connection with a Committed Equity Financing Facility (CEFF) (net of expenses)	3,720,104	407	3,719,697
Issuance of shares of common stock in connection with a Committed Equity Financing Facility (CEFF) (net of expenses), Shares	406,744	406,744
Share-based compensation expense	727,156		727,156
Net loss	(19,922,515)			(19,922,515)
Ending Balance at Dec. 31, 2010	31,798,968	25,263	130,916,326	(99,142,621)
Ending Balance, Shares at Dec. 31, 2010		25,262,538
Exercise of options	13,350	5	13,345
Exercise of options, Shares	5,000	5,000
Issuance of common stock award	172,000	40	171,960
Issuance of common stock award, Shares		40,000
Issuance of shares of common stock in connection with a public offering (net of expenses)	15,024,662	5,000	15,019,662
Issuance of shares of common stock in connection with a public offering (net of expenses), Shares		5,000,000
Share-based compensation expense	3,183,131		3,183,131
Net loss	(20,384,715)			(20,384,715)
Ending Balance at Dec. 31, 2011	29,807,396	30,308	149,304,424	(119,527,336)
Ending Balance, Shares at Dec. 31, 2011	30,307,538	30,307,538
Exercise of options	44,759	21	44,738
Exercise of options, Shares	61,796	21,484
Cashless exercise of options		12	(12)
Cashless exercise of options, Shares		11,868
Issuance of shares of common stock in connection with a public offering (net of expenses)	5,308,037	1,864	5,306,173
Issuance of shares of common stock in connection with a public offering (net of expenses), Shares		1,863,830
Share-based compensation expense	1,487,550		1,487,550
Net loss	(22,672,532)			(22,672,532)
Ending Balance at Dec. 31, 2012	$ 13,975,210	$ 32,205	$ 156,142,873	$ (142,199,868)
Ending Balance, Shares at Dec. 31, 2012	32,204,720	32,204,720