Note 4 - Investments - Net Investment Income (Details) - USD ($)	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Interest on cash and cash equivalents	$ 1,696	$ 2,070
Dividends on marketable securities	1	1
Net investment income	$ 1,697	$ 2,071

Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
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-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.5-03(7)(b))
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-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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