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Fair Value (Details Textual) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Fair Value Disclosures [Abstract]      
Cash Equivalent Maturity Period Description 90 days or less    
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax $ 0 $ 0 $ 0