Accounts Receivable (Tables)

6 Months Ended

Jan. 31, 2020

Accounts Receivable Additional Disclosures [Abstract]

Accounts receivable

Accounts receivable consist of the following at:

	January 31, 2020		July 31, 2019
Receivables from commercial and international customers	$	77,080,000	85,556,000
Unbilled receivables from commercial and international customers	23,795,000		20,469,000
Receivables from the U.S. government and its agencies	45,008,000		38,856,000
Unbilled receivables from the U.S. government and its agencies	3,202,000		2,018,000
Total accounts receivable	149,085,000		146,899,000
Less allowance for doubtful accounts	1,102,000		1,867,000
Accounts receivable, net	$	147,983,000	145,032,000