Inventories (Details) - USD ($)	Oct. 31, 2021	Jul. 31, 2021
Inventory Disclosure [Abstract]
Raw materials and components	$ 67,151,000	$ 62,249,000
Work-in-process and finished goods	41,606,000	38,338,000
Total inventories	108,757,000	100,587,000
Less reserve for excess and obsolete inventories	21,061,000	20,229,000
Inventories, net	87,696,000	80,358,000
Inventory directly related to long-term contracts	7,392,000	7,028,000
Inventory related to contracts from third party commercial customers who outsource their manufacturing to us	$ 1,632,000	$ 1,509,000