Accounts Receivable (Details) - USD ($)	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Total accounts receivable	$ 70,461,000	$ 55,514,000
Less: Allowance for doubtful accounts	1,206,000	627,000
Accounts receivable, net	$ 69,255,000	$ 54,887,000
Accounts Receivable [Member] | Customer Concentration Risk [Member] | U.S. Prime Contractor [Member]
Percentage of total accounts receivable	36.30%	18.00%
Billed Receivables [Member] | Commercial Customers [Member]
Total accounts receivable	$ 39,062,000	$ 31,681,000
Billed Receivables [Member] | U.S. Government and Its Agencies [Member]
Total accounts receivable	8,375,000	10,316,000
Unbilled Receivables on Contracts-In-Progress [Member]
Total accounts receivable	23,024,000	13,517,000
Retainage included in unbilled receivables	0	120,000
Unbilled Receivables on Contracts-In-Progress [Member] | Customer Concentration Risk [Member] | U.S. Prime Contractor [Member]
Unbilled receivable related to our large over-the-horizon microwave system contracts	20,256,000	9,990,000
Unbilled Receivables on Contracts-In-Progress [Member] | U.S. Government and Its Agencies [Member]
Unbilled receivables on contracts-in-progress due from U.S. government and its agencies	$ 1,126,000	$ 770,000