Supplemental Financial Information (Details) (USD $)	3 Months Ended								10 Months Ended	12 Months Ended														178 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 1999	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009	Mar. 31, 2008	Mar. 31, 2007	Mar. 31, 2006	Mar. 31, 2005	Mar. 31, 2004	Mar. 31, 2003	Mar. 31, 2002	Mar. 31, 2001	Mar. 31, 2000	Mar. 31, 2013
Revenues:
Grant revenue				$ 200,000	$ 469,000	$ 2,000	$ 316,000	$ 555,000		$ 200,400	$ 1,342,200													$ 12,963,100
Total revenues				200,000	469,000	2,000	316,000	555,000		200,400	1,342,200													16,370,200
Operating expenses:
Research and development	339,000	1,120,000	1,106,000	866,000	1,828,000	1,306,000	1,227,000	1,028,000		3,430,800	5,388,600													29,555,700
General and administrative	1,132,000	799,000	576,000	1,055,000	1,428,000	1,548,000	894,000	1,127,000		3,562,700	4,997,000													30,681,100
Total operating expenses	1,471,000	1,919,000	1,682,000	1,921,000	3,256,000	2,854,000	2,121,000	2,155,000		6,993,500	10,385,600													67,760,000
Loss from operations	(1,471,000)	(1,919,000)	(1,682,000)	(1,721,000)	(2,787,000)	(2,852,000)	(1,805,000)	(1,600,000)		(6,793,100)	(9,043,400)													(51,389,800)
Other expenses, net:
Interest expense, net	(309,000)	(235,000)	(274,000)	(103,000)	(256,000)	(455,000)	(451,000)	(731,000)		(920,700)	(1,893,200)													(10,362,200)
Change in put and note extension option and warrant liabilities	(1,994,000)	358,000						(78,000)		(1,635,800)	(78,000)													(1,217,300)
Loss on early extinguishment of debt	(31,000)	(3,537,000)				(1,193,000)				(3,567,800)	(1,193,500)													(4,761,300)
Other income	35,000									34,400	200													81,900
Loss before income taxes	(3,770,000)	(5,333,000)	(1,956,000)	(1,824,000)	(3,043,000)	(4,500,000)	(2,256,000)	(2,409,000)		(12,883,000)	(12,207,900)													(67,648,700)
Income taxes		(2,000)		(2,000)				(2,000)		3,700	1,600													20,500
Net loss	$ (3,770,000)	$ (5,335,000)	$ (1,956,000)	$ (1,826,000)	$ (3,043,000)	$ (4,500,000)	$ (2,256,000)	$ (2,411,000)	$ (230,900)	$ (12,886,700)	$ (12,209,500)	$ (9,482,200)	$ (4,124,500)	$ (4,696,200)	$ (5,446,700)	$ (1,999,800)	$ (1,772,100)	$ (1,082,800)	$ (8,755,500)	$ (502,600)	$ (2,113,000)	$ (1,809,000)	$ (700,000)	$ (67,669,200)
Basic and diluted net loss per common share	$ (0.19)	$ (0.85)	$ (0.11)	$ (0.11)	$ (0.18)	$ (0.28)	$ (0.15)	$ (0.22)		$ (1.27)	$ (0.83)
Weighted average shares used in computing basic and diluted net loss per common share	20,236,491	18,292,301	17,094,833	16,842,655	16,542,717	16,035,861	15,241,904	11,105,854		18,108,444	14,736,651