Fair Value (Assets and Liabilities Measured on a Recurring Basis) (Details) (USD $)	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities- unrestricted	$ 21,898,000			$ 26,229,000
Marketable securities- restricted	10,342,000			1,026,000
Warrants	2,112,000			380,000
Derivative, Fair Value, Net	0
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities- unrestricted	12,698,000
Marketable securities- restricted	6,800,000
Warrants	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable securities- unrestricted	9,200,000
Marketable securities- restricted	3,542,000
Warrants	0
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	2,112,000
Warrant [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Warrants	2,112,000	144,000	531,000	380,000	1,247,000	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	$ 1,968,000	$ (387,000)	$ 151,000		$ (613,000)	$ (643,000)	$ (302,000)