Annual report pursuant to Section 13 and 15(d)

Short-Term Investments (Schedule of Short Term Investments) (Details)

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Short-Term Investments (Schedule of Short Term Investments) (Details) - Certificates of deposit, commercial paper [Member] - USD ($)
Dec. 31, 2018
Dec. 31, 2017
Estimated fair value $ 5,570,027
Gross unrealized losses (131)
Amortized cost $ 5,570,158