Note 6 - Stock-based Compensation - Stock Option Valuation Assumptions (Details)	9 Months Ended
Jun. 30, 2018	Jul. 01, 2017
Risk-free interest rate	2.72%	2.03%
Dividend yield	0.40%	0.33%
Expected volatility	37.74%	38.79%
Expected term (Year)	4 years 324 days	5 years 43 days

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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