Inventories (Details) - USD ($)	Sep. 30, 2024	Dec. 31, 2023
Inventories
Raw materials	$ 30,535,000	$ 32,910,000
Work in process	52,676,000	50,008,000
Finished goods	2,898,000	3,585,000
Inventories, Total	86,109,000	86,503,000
Inventory reserve	23,200,000	21,900,000
Excess and obsolete inventory	$ 68,000	$ 78,000