Accounts Receivable (Tables)

6 Months Ended

Jan. 31, 2021

Receivables [Abstract]

Accounts receivable

Accounts receivable consist of the following at:

	January 31, 2021		July 31, 2020
Receivables from commercial and international customers	$	77,551,000	67,109,000
Unbilled receivables from commercial and international customers	25,137,000		21,588,000
Receivables from the U.S. government and its agencies	43,241,000		32,870,000
Unbilled receivables from the U.S. government and its agencies	6,101,000		7,018,000
Total accounts receivable	152,030,000		128,585,000
Less allowance for doubtful accounts	2,102,000		1,769,000
Accounts receivable, net	$	149,928,000	126,816,000