Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Schedule Of Financial Assets And Liabilities Measured At Fair Value) (Details)

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Fair Value Measurements (Schedule Of Financial Assets And Liabilities Measured At Fair Value) (Details) - USD ($)
Mar. 31, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents $ 7,303,000 $ 3,851,000
Assets (Liabilities) Net, fair value 9,671,000 9,656,000
Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 7,303,000 3,851,000
Assets (Liabilities) Net, fair value 7,303,000 3,851,000
Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets (Liabilities) Net, fair value 2,368,000 5,805,000
Money Market Funds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 7,303,000 3,851,000
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 7,303,000 3,851,000
Short-Term Investments [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 2,368,000 5,805,000
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 2,368,000 5,805,000
Short-Term Investments [Member] | Certificates Of Deposit [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 2,368,000 4,294,000
Short-Term Investments [Member] | Certificates Of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments $ 2,368,000 4,294,000
Short-Term Investments [Member] | Corporate Notes/Bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments   1,511,000
Short-Term Investments [Member] | Corporate Notes/Bonds [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments   $ 1,511,000