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FAIR VALUE OF FINANCIAL INSTRUMENTS - Valuation of Securities Using Fair Value Hierarchy (Details) - USD ($)
Mar. 31, 2020
Dec. 31, 2019
United States Contracts    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure $ (20,758,656) $ 3,602,591
Short-Term Investments    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure 29,917,445 50,852,898
Fair Value, Inputs, Level 1 [Member] | United States Contracts    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure (20,758,656) 3,602,591
Fair Value, Inputs, Level 1 [Member] | Short-Term Investments    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure 29,917,445 50,852,898
Fair Value, Inputs, Level 2 [Member] | United States Contracts    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure 0 0
Fair Value, Inputs, Level 2 [Member] | Short-Term Investments    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure 0 0
Fair Value, Inputs, Level 3 [Member] | United States Contracts    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure 0 0
Fair Value, Inputs, Level 3 [Member] | Short-Term Investments    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Investments, Fair Value Disclosure $ 0 $ 0