Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	8 Months Ended	9 Months Ended	12 Months Ended															185 Months Ended	194 Months Ended	197 Months Ended
	Mar. 31, 1997	Dec. 31, 2003	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006	Dec. 31, 2005	Dec. 31, 2004	Mar. 31, 2003	Mar. 31, 2002	Mar. 31, 2001	Mar. 31, 2000	Mar. 31, 1999	Mar. 31, 1998	Dec. 31, 2011	Sep. 30, 2012	Dec. 31, 2012
Geographic information
Revenue			$ 69		$ 112															$ 6,817
Net loss	(290)	(14,977)	(13,186)	(15,243)	(16,021)	(19,570)	(40,386)	(24,053)	(29,258)	(18,048)	(22,742)	(15,542)	(14,853)	(10,382)	(5,686)	(3,964)	(2,534)	(253,549)	(261,971)	(266,735)
Total Assets			19,354	25,998														25,998		19,354
Long Lived Assets, net			129	167	167													167		129
United States
Geographic information
Net loss			(1,102)	(75)	(4,662)
Total Assets			15,500	20,715														20,715		15,500
Long Lived Assets, net			25	45														45		25
United States | Continuing operations
Geographic information
Net loss			(1,672)	565	(3,531)
Total Assets			14,286	20,402														20,402		14,286
Long Lived Assets, net			25	45														45		25
United States | Discontinued operations
Geographic information
Net loss			570	(640)	(1,131)
Total Assets			1,214	313														313		1,214
United Kingdom
Geographic information
Revenue			69		112
Net loss			(12,084)	(15,168)	(11,359)
Total Assets			3,854	5,283														5,283		3,854
Long Lived Assets, net			$ 104	$ 122														$ 122		$ 104