Accounts Receivable (Tables)

6 Months Ended

Jan. 31, 2018

Accounts Receivable Additional Disclosures [Abstract]

Accounts receivable

Accounts receivable consist of the following at:

	January 31, 2018		July 31, 2017
Billed receivables from commercial and international customers	$	68,478,000	71,404,000
Unbilled receivables from commercial and international customers	14,726,000		24,668,000
Billed receivables from the U.S. government and its agencies	21,235,000		18,497,000
Unbilled receivables from the U.S. government and its agencies	15,410,000		11,693,000
Total accounts receivable	119,849,000		126,262,000
Less allowance for doubtful accounts	1,876,000		1,300,000
Accounts receivable, net	$	117,973,000	124,962,000