Accounts Receivable

12 Months Ended

Jul. 31, 2011

Accounts Receivable, Net [Abstract]

Accounts Receivable

(3) Accounts Receivable

Accounts receivable consist of the following at July 31, 2011 and 2010:

	2011	2010
Billed receivables from commercial customers	$    38,245,000	35,230,000
Billed receivables from the U.S. government and its agencies	22,075,000	89,843,000
Unbilled receivables on contracts-in-progress	11,701,000	11,894,000
Total accounts receivable	72,021,000	136,967,000
Less allowance for doubtful accounts	1,220,000	1,127,000
Accounts receivable, net	$    70,801,000	135,840,000

Unbilled receivables on contracts-in-progress include $4,487,000 and $11,430,000 at July 31, 2011 and July 31, 2010, respectively, due from the U.S. government and its agencies. There was $28,000 of retainage included in unbilled receivables at both July 31, 2011 and July 31, 2010. In the opinion of management, substantially all of the unbilled balances will be billed and collected within one year.