Note 3 - Stock-based Compensation - Stock-based Compensation Costs (Details) - USD ($)	3 Months Ended	6 Months Ended
Mar. 27, 2021	Mar. 28, 2020	Mar. 27, 2021	Mar. 28, 2020
Stock-based compensation costs	$ 13,400	$ 13,976	$ 27,263	$ 26,751
Selling, General and Administrative Expenses [Member]
Stock-based compensation costs	10,910	10,161	22,282	21,243
Product Development Expenses [Member]
Stock-based compensation costs	$ 2,490	$ 3,815	$ 4,981	$ 5,508

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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