Inventories (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Inventories
Raw materials	$ 32,910,000	$ 46,476,000
Work in process	50,008,000	39,956,000
Finished goods	3,585,000	3,197,000
Inventories, Total	86,503,000	89,629,000
Inventory reserve	21,900,000	24,700,000
Excess and obsolete inventory	$ 78,000	$ 47,000