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Marketable Investment Securities (Details) - USD ($)
Sep. 30, 2019
Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 4,880,615 $ 7,174,000
Gross unrealized holding gains 261 0
Gross unrealized holding losses 0 (963)
Aggregate fair value 4,880,876 7,173,037
Government bonds and notes [Member]    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 849,887 897,481
Gross unrealized holding gains 36 0
Gross unrealized holding losses 0 (100)
Aggregate fair value 849,923 897,381
Corporate Bonds, Notes and Commercial Paper [Member]    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 4,030,728 6,276,519
Gross unrealized holding gains 225 0
Gross unrealized holding losses 0 (863)
Aggregate fair value $ 4,030,953 $ 6,275,656