Composition Of Certain Financial Statement Captions (Schedule Of Accounts Receivable) (Details) (USD $) In Thousands | Sep. 30, 2011 | Sep. 24, 2010 |
|---|---|---|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Accounts receivable, gross | $ 64,281 | $ 56,297 |
| Less: allowance for doubtful accounts | (2,466) | (2,040) |
| Accounts receivable, net | 61,815 | 54,257 |
Trade Accounts Receivable [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Trade accounts receivable | 59,831 | 45,651 |
Patent Administration Program [Member] | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Accounts receivable related to patent administration program | $ 4,450 | $ 10,646 |