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Note 6 - Employee Benefit Plans (Details Textual) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 27, 2025 | Dec. 28, 2024 | Dec. 30, 2023
Defined Contribution Plan, Employer Matching Contribution, Percent of Match | 50.00% |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay | 8.00% |  |
Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 2,200 | $ 2,300 | $ 2,500
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment | 2,159 | 0 | $ 0
Deferred Compensation Liability, Current | 400 | 600 |
Cash Surrender Value of Life Insurance | $ 1,500 | $ 1,400 |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares) | 0 | 0 | 0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number (in shares) | 0 | 0 |
Restricted Stock Units (RSUs) [Member] | Vesting Over One Year Period [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | 1 year |  |
Restricted Stock Units (RSUs) [Member] | Vesting Over Two Year Period [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | 2 years |  |
Restricted Stock Units (RSUs) [Member] | Vesting Over Three Year Period [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | 3 years |  |
Restricted Stock Units (RSUs) [Member] | Vesting Over Four Year Period [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | 4 years |  |
Equity Based Performance Stock Units Granted in 2020, 2019, 2018, and 2017 [Member] | Vest on the Third Anniversary of Awards Grant [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage | 100.00% |  |
Unvested Restricted Stock Units [Member] |  |  |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ 25,100 |  |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) | 1 year 8 months 12 days |  |
Minimum [Member] | Performance Shares [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Shares Available for Issue | 0.00% |  |
Maximum [Member] | Performance Shares [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Shares Available for Issue | 200.00% |  |
Equity Incentive Plan 2005 [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 1,841,531 |  |
Percentage of Fair Value to Determine Price of Common Stock | 100.00% |  |
Equity Incentive Plan 2005 [Member] | Share-Based Payment Arrangement, Option [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) | 10 years |  |
Equity Incentive Plan 2005 [Member] | Minimum [Member] | Share-Based Payment Arrangement, Option [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | 1 year |  |
Equity Incentive Plan 2005 [Member] | Maximum [Member] | Share-Based Payment Arrangement, Option [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) | 4 years |  |
Employee Stock Purchase Plan [Member] |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 353,581 |  |
Employee Stock Purchase Plan, Shares Reserved for Future Issuance (in shares) | 3,750,000 |  |
Percentage of Fair Value to Determine Price of Common Stock | 85.00% |  |
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares) | 274,735 | 171,353 | 146,829
Postretirement Health Coverage [Member] |  |  |
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) | $ (211) | $ 25 |
Defined Benefit Plan, Expected Future Benefit Payment, Year One | 100 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Two | 100 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Three | 100 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Four | 100 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Five | 100 |  |
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years | 700 |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) | $ 100 | $ 100 | $ 100
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate | 5.10% | 5.40% | 4.70%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate | 4.50% |  |
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year | $ 100 |  |
Swiss Plan [Member] |  |  |
Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Tax | 3,900 | $ 4,000 |
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) | 2,705 | 79 |
Defined Benefit Plan, Expected Future Employee and Employer Contributions, Next Twelve Months | 400 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year One | 900 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Two | 1,000 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Three | 600 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Four | 500 |  |
Defined Benefit Plan, Expected Future Benefit Payment, Year Five | 500 |  |
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years | 3,600 |  |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment | 2,159 | (0) | $ (0)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) | $ (3,361) | $ 440 | $ 553
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate | 1.30% | 1.10% |
Swiss Plan [Member] | Debt Securities and Cash [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 45.00% |  |
Swiss Plan [Member] | Real Estate Investments [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 24.00% |  |
Swiss Plan [Member] | Alternative Investments [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 13.00% |  |
Swiss Plan [Member] | Defined Benefit Plan, Equity Securities [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 18.00% |  |
Post Age 65 Plan [Member] | Postretirement Health Coverage [Member] |  |  |
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year | 10.70% |  |
Pre Age 65 Plan [Member] | Postretirement Health Coverage [Member] |  |  |
Defined Benefit Plan, Health Care Cost Trend Rate, Annual Rate of Change | 0.69% |  |

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- Definition The annual rate of change increase (decrease) in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status. + References No definition available. + Details
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- Definition Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(17)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
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- Definition Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable within one year (or the operating cycle, if longer). Represents currently earned compensation under compensation arrangements that is not actually paid until a later date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 710 -SubTopic 10 -Name Accounting Standards Codification -Section 25 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483070/710-10-25-9 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 30 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483043/710-10-30-2 + Details
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- Definition Amount, after tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482790/220-10-45-14A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (j) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of benefit for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of benefit for defined benefit plan expected to be paid in next fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of benefit for defined benefit plan expected to be paid in fourth fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of benefit for defined benefit plan expected to be paid in third fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of benefit for defined benefit plan expected to be paid in second fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-18 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (l) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-18 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-6 + Details
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from event reducing expected years of future service of present employees or eliminating accrual of defined benefits for some or all future services of present employees. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480535/715-20-45-3A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(7) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(7) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-6 + Details
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- Definition Ultimate trend rate for health care cost for defined benefit postretirement plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (k) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (l) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
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- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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