|
Accounts Receivable (Details) (USD $)
|
Apr. 30, 2011
|
Jul. 31, 2010
|
|---|---|---|
| Total accounts receivable | $ 71,565,000 | $ 136,967,000 |
| Less: Allowance for doubtful accounts | 1,380,000 | 1,127,000 |
| Accounts receivable, net | 70,185,000 | 135,840,000 |
| Unbilled receivables on contracts-in-progress due from US government and its agencies | 2,735,000 | 11,430,000 |
| Retainage included in unbilled receivables | 28,000 | 28,000 |
|
Billed Receivables [Member] | U.S. Government and its agencies [Member]
|
 |  |
| Total accounts receivable | 23,349,000 | 89,843,000 |
|
Billed Receivables [Member] | Non-U.S. Government Customer [Member]
|
 |  |
| Total accounts receivable | 36,311,000 | 35,230,000 |
|
Unbilled Receivables on Contracts-in-Progress [Member]
|
 |  |
| Total accounts receivable | $ 11,905,000 | $ 11,894,000 |