Inventories (Details) - USD ($)	Oct. 31, 2017	Jul. 31, 2017
Inventory Disclosure [Abstract]
Raw materials and components	$ 51,237,000	$ 50,569,000
Work-in-process and finished goods	34,188,000	26,053,000
Total inventories	85,425,000	76,622,000
Less reserve for excess and obsolete inventories	15,234,000	16,019,000
Inventories, net	70,191,000	60,603,000
Inventory directly related to long-term contracts	2,018,000	2,148,000
Inventory related to contracts from third party commercial customers who outsource their manufacturing to us	$ 1,507,000	$ 1,718,000