Note 7 - Income Taxes - Significant Components of Deferred Tax Liabilities and Assets (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Property and equipment	$ (1,255,000)	$ (1,055,000)
Total deferred tax liabilities	(1,255,000)	(1,055,000)
Net operating loss carryforwards	139,000	360,000
Accruals and allowances	167,000	41,000
Lease liabilities	61,000	136,000
Tax credits	3,000	4,000
Other – net	114,000	87,000
Capital loss carryover	646,000	646,000
Total deferred tax assets	1,130,000	1,274,000
Valuation allowance	(697,000)	(697,000)
Deferred tax assets net of valuation allowance	433,000	577,000
Net deferred tax liabilities	$ (822,000)	$ (478,000)