Note 5 - Share-based Compensation Plans - Annualized Weighted Average Values of Significant Assumptions Used to Estimate Fair Values (Details) - $ / shares	12 Months Ended
Dec. 25, 2021	Dec. 26, 2020
Expected volatility	54.00%
Expected dividend yield	0.00%
Weighted average fair value of grants (in dollars per share)	$ 1.72	$ 78
Minimum [Member]
Risk-free interest rate (Rate)	50.00%	84.00%
Expected life in years (Year)	6 years	6 years
Maximum [Member]
Risk-free interest rate (Rate)	1.34%	91.00%
Expected life in years (Year)	7 years	7 years
Expected volatility		54.00%
Expected dividend yield		0.00%
Weighted average fair value of grants (in dollars per share)	$ 1.72

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.

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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

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
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-Name Accounting Standards Codification
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=122041274&loc=d3e301413-122809

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