Note 5 - Share-based Payments (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Oct. 01, 2022	Sep. 25, 2021	Oct. 01, 2022	Sep. 25, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)	0	500
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period (in shares)	10,000	32,500
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Expirations in Period (in shares)	0	0
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price (in dollars per share)		$ 1.49
Stock Repurchased During Period, Shares (in shares)	0	112
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)	983,100		983,100
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)	$ 2.44		$ 2.44
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	6 years 3 months 18 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number (in shares)	518,800		518,800
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 2.03		$ 2.03
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)	4 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	1,500,000		1,500,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)	915,800		915,800
Share-Based Payment Arrangement, Expensed and Capitalized, Amount, Total	$ 43	$ 28	$ 207	$ 148
Equity Incentive Plan Stock Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)	25,000	5,000

Number of shares authorized for issuance under share-based payment arrangement.

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-Publisher FASB
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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Amount of cost expensed and capitalized for award under share-based payment arrangement.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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