Fair Value Measurements (Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Secured Contingent Payment Obligation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	$ 14,185,447
Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	13,618	$ 1,789,947
Restricted Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	910,838
Quoted Prices In Active Markets (Level 1) [Member] | Secured Contingent Payment Obligation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities
Quoted Prices In Active Markets (Level 1) [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	13,618	1,789,947
Quoted Prices In Active Markets (Level 1) [Member] | Restricted Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	910,838
Significant Other Observable Inputs (Level 2) [Member] | Secured Contingent Payment Obligation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities
Significant Other Observable Inputs (Level 2) [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets
Significant Other Observable Inputs (Level 2) [Member] | Restricted Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets
Significant Unobservable Inputs (Level 3) [Member] | Secured Contingent Payment Obligation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	14,185,447
Significant Unobservable Inputs (Level 3) [Member] | Available For Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets
Significant Unobservable Inputs (Level 3) [Member] | Restricted Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets