Quarterly report pursuant to Section 13 or 15(d)

Assets and Liabilities, at Fair Value - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Details)

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Assets and Liabilities, at Fair Value - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Parenthetical) (Details) - USD ($)
Sep. 30, 2020
Jun. 30, 2020
Jun. 30, 2019
Fair Value Disclosures [Abstract]      
Commemorative coin inventory, held at lower of cost or net realizable value $ 9,000 $ 17,000 $ 17,000