Summary of Significant Accounting Policies (Financial Assets and Liabilities Measured at Fair Market Value on a Recurring Basis)(Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate debt and auction rate securities	$ 17,672	$ 4,205
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate debt and auction rate securities
Warrant liability
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate debt and auction rate securities	17,672	4,205
Warrant liability
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Corporate debt and auction rate securities
Warrant liability	$ 769	$ 368