Inventories (Details) - USD ($)	Jan. 31, 2018	Jul. 31, 2017
Inventory Disclosure [Abstract]
Raw materials and components	$ 52,592,000	$ 50,569,000
Work-in-process and finished goods	35,162,000	26,053,000
Total inventories	87,754,000	76,622,000
Less reserve for excess and obsolete inventories	16,047,000	16,019,000
Inventories, net	71,707,000	60,603,000
Inventory directly related to long-term contracts	1,420,000	2,148,000
Inventory related to contracts from third party commercial customers who outsource their manufacturing to us	$ 1,528,000	$ 1,718,000