Accounts Receivable (Tables)

3 Months Ended

Oct. 31, 2012

Accounts Receivable Additional Disclosures [Abstract]

Accounts receivable

	October 31, 2012		July 31, 2012
Billed receivables from commercial customers	$	35,209,000	41,139,000
Billed receivables from the U.S. government and its agencies	9,013,000		11,927,000
Unbilled receivables on contracts-in-progress	4,070,000		4,764,000
Total accounts receivable	48,292,000		57,830,000
Less allowance for doubtful accounts	1,365,000		1,588,000
Accounts receivable, net	$	46,927,000	56,242,000