Fair Value (Assets and Liabilities Measured on a Recurring Basis) (Details) (USD $)	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities- unrestricted	$ 19,442,000		$ 26,229,000
Marketable securities- restricted	7,343,000		1,026,000
Warrants	(144,000)		(380,000)
Total	26,641,000
Derivative, Fair Value, Net	0
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities- unrestricted	17,384,000
Marketable securities- restricted	1,010,000
Warrants	0
Total	18,394,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities- unrestricted	2,058,000
Marketable securities- restricted	6,333,000
Warrants	0
Total	8,391,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities- unrestricted	0
Marketable securities- restricted	0
Warrants	(144,000)
Total	(144,000)
Warrant [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Warrants	(144,000)	(531,000)	(380,000)	(1,860,000)	(2,503,000)	(2,805,000)
Warrant [Member] | Change During Period, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Warrants	$ 387,000	$ (151,000)		$ 643,000	$ 302,000