Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Common Stock Subscribed but Unissued [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Beginning Balance at Sep. 30, 2010	$ 28,006,556	$ 9,597	$ 580,910	$ 332,100,685	$ (304,684,636)
Beginning Balance, Shares at Sep. 30, 2010		95,965,572	180,000
Net loss	(60,631,563)				(60,631,563)
Issuance of common stock in connection with:
Exercise of stock options	638,076	81		637,995
Exercise of stock options, Shares		814,454
Exercise of warrants	8,701,931	608		8,701,323
Exercise of warrants, Shares		6,085,267
Sale of stock, net of offering costs	90,851,876	2,233	(580,910)	91,430,553
Sale of stock, net of offering costs, Shares		22,327,000	(180,000)
Vesting of restricted stock units		25		(25)
Vesting of restricted stock units, Shares		252,941
Common stock surrendered	(5,665)			(5,665)
Common stock surrendered, Shares		(1,446)
Share-based compensation expense	3,778,453			3,778,453
Ending Balance at Sep. 30, 2011	71,339,664	12,544		436,643,319	(365,316,199)
Ending Balance, Shares at Sep. 30, 2011		125,443,788
Net loss	(59,743,827)				(59,743,827)
Issuance of common stock in connection with:
Exercise of stock options	1,345,128	167		1,344,961
Exercise of stock options, Shares	1,673,811	1,673,811
Exercise of warrants	7,786,437	545		7,785,892
Exercise of warrants, Shares	5,445,061	5,445,061
Sale of stock, net of offering costs	10,062,996	367		10,062,629
Sale of stock, net of offering costs, Shares	3,668,656	3,668,656
Vesting of restricted stock units		20		(20)
Vesting of restricted stock units, Shares		204,176
Issuance of warrants to purchase common stock in connection with notes payable	1,169,227			1,169,227
Share-based compensation expense	4,877,482			4,877,482
Ending Balance at Sep. 30, 2012	36,837,107	13,643		461,883,490	(425,060,026)
Ending Balance, Shares at Sep. 30, 2012	136,435,492	136,435,492
Net loss	(75,475,863)				(75,475,863)
Issuance of common stock in connection with:
Exercise of stock options	1,496,254	103		1,496,151
Exercise of stock options, Shares	1,033,833	1,033,833
Exercise of warrants	1,015,457	78		1,015,379
Exercise of warrants, Shares	1,147,159	782,294
Sale of stock, net of offering costs	48,752,806	1,297		48,751,509
Sale of stock, net of offering costs, Shares		12,965,465
Vesting of restricted stock units		85		(85)
Vesting of restricted stock units, Shares		846,537
Share-based compensation expense	5,845,793			5,845,793
Ending Balance at Sep. 30, 2013	$ 18,471,554	$ 15,206		$ 518,992,237	$ (500,535,889)
Ending Balance, Shares at Sep. 30, 2013	152,063,621	152,063,621