Accounts Receivable (Tables)

9 Months Ended

Apr. 30, 2017

Accounts Receivable Additional Disclosures [Abstract]

Accounts receivable

Accounts receivable consist of the following at:

	April 30, 2017		July 31, 2016
Billed receivables from commercial and international customers	$	69,149,000	90,185,000
Unbilled receivables from commercial and international customers	24,929,000		19,333,000
Billed receivables from the U.S. government and its agencies	16,918,000		21,465,000
Unbilled receivables from the U.S. government and its agencies	10,927,000		21,013,000
Total accounts receivable	121,923,000		151,996,000
Less allowance for doubtful accounts	1,475,000		1,029,000
Accounts receivable, net	$	120,448,000	150,967,000