Accounts Receivable (Tables)

6 Months Ended

Jan. 31, 2013

Accounts Receivable Additional Disclosures [Abstract]

Accounts receivable

	January 31, 2013		July 31, 2012
Billed receivables from commercial customers	$	30,082,000	41,139,000
Billed receivables from the U.S. government and its agencies	9,094,000		11,927,000
Unbilled receivables on contracts-in-progress	4,107,000		4,764,000
Total accounts receivable	43,283,000		57,830,000
Less allowance for doubtful accounts	1,047,000		1,588,000
Accounts receivable, net	$	42,236,000	56,242,000