Note 4 - Marketable Securities (Details Textual) - USD ($) |
Jun. 30, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Accrued Interest Receivable On Available For Sale Securities [Member] | ||
| Interest Receivable | $ 18,000 | $ 25,000 |
| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Details
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