Income taxes (Details - Deferred tax assets) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax liabilities attributable to:
Accumulated depreciation and amortization	$ (3,519)	$ (3,394)
Unrealized gains	(469)	(472)
Total deferred tax liabilities	(3,988)	(3,866)
Deferred tax assets attributable to:
Net operating losses	6	6
Accrued compensation	403	287
Incentive compensation	301	194
Inventory	280	328
Allowances for doubtful accounts and discounts	3	5
Other	(6)	17
Total net deferred tax assets	987	837
Net deferred tax liabilities	$ (3,001)	$ (3,029)