Accounts Receivable (Details) (USD $)			9 Months Ended
	Apr. 30, 2014	Jul. 31, 2013	Apr. 30, 2014 Accounts Receivable [Member] Credit Concentration Risk [Member]	Apr. 30, 2014 Billed Receivables [Member] Commercial Customers [Member]	Jul. 31, 2013 Billed Receivables [Member] Commercial Customers [Member]	Apr. 30, 2014 Billed Receivables [Member] U.S. Government and Its Agencies [Member]	Jul. 31, 2013 Billed Receivables [Member] U.S. Government and Its Agencies [Member]	Apr. 30, 2014 Unbilled Receivables on Contracts-In-Progress [Member]	Jul. 31, 2013 Unbilled Receivables on Contracts-In-Progress [Member]
Total accounts receivable	$ 65,729,000	$ 50,518,000		$ 36,956,000	$ 40,005,000	$ 8,892,000	$ 8,114,000	$ 19,881,000	$ 2,399,000
Less allowance for doubtful accounts	705,000	603,000
Accounts receivable, net	65,024,000	49,915,000
Unbilled receivable related to one of our large over-the-horizon microwave system contracts								15,044,000
Unbilled receivables on contracts-in-progress due from U.S. government and its agencies								2,881,000	699,000
Retainage included in unbilled receivables								$ 0	$ 0
Percentage of total accounts receivable from the prime contractor that we perform work for on our two North African country end-customer contracts			28.40%