Note 3 - Inventories - Schedule of Inventory (Details) - USD ($)	Sep. 30, 2024	Dec. 31, 2023
Raw material and common parts	$ 7,964,000	$ 7,828,000
Work-in-process	7,499,000	6,466,000
Finished goods	680,000	531,000
Inventory, Gross	16,143,000	14,825,000
Less inventory reserve	(735,000)	(627,000)
Total inventories	$ 15,408,000	$ 14,198,000