Accounts Receivable (Details) (USD $)	6 Months Ended	12 Months Ended
	Jan. 31, 2015	Jul. 31, 2014
Total accounts receivable	69,596,000	55,514,000
Less allowance for doubtful accounts	700,000	627,000
Accounts receivable, net	68,896,000	54,887,000
Accounts Receivable [Member] | Major customer | U.S. Prime Contractor
Percentage of total accounts receivable	37.10%	18.00%
Billed Receivables [Member] | Commercial Customers [Member]
Total accounts receivable	36,759,000	31,681,000
Billed Receivables [Member] | U.S. Government and Its Agencies [Member]
Total accounts receivable	10,285,000	10,316,000
Unbilled Receivables on Contracts-In-Progress [Member]
Total accounts receivable	22,552,000	13,517,000
Unbilled receivables on contracts-in-progress due from U.S. government and its agencies	490,000	770,000
Retainage included in unbilled receivables	0	120,000
Unbilled Receivables on Contracts-In-Progress [Member] | Major customer | U.S. Prime Contractor
Unbilled receivable related to our large over-the-horizon microwave system contracts	21,164,000	9,990,000