Note 3 - Stock-based Compensation - Stock-based Compensation Costs (Details) - USD ($)	3 Months Ended	6 Months Ended
Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Stock-based compensation costs	$ 13,976	$ 8,784	$ 26,751	$ 17,584
Selling, General and Administrative Expenses [Member]
Stock-based compensation costs	10,161	7,587	21,243	15,183
Product Development Expenses [Member]
Stock-based compensation costs	$ 3,815	$ 1,197	$ 5,508	$ 2,401

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

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