Note 6 - Employee Benefit Plans (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2024	Dec. 30, 2023	Dec. 31, 2022
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	$ 2,300	$ 2,500	$ 2,400
Deferred Compensation Liability, Current	600	900
Cash Surrender Value of Life Insurance	$ 1,400	$ 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, Exercises in Period, Intrinsic Value			$ 200
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 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	$ 27,500
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	1 year 10 months 24 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)	2,946,601
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)	628,316
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)	171,353	146,829	160,855
Postretirement Health Coverage [Member]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 25	$ (6)
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	5.40%	4.70%	4.90%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	4.40%
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	4,000	$ 4,200
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	79	(1,391)
Defined Benefit Plan, Expected Future Employee and Employer Contributions, Next Twelve Months	700
Defined Benefit Plan, Expected Future Benefit Payment, Year One	800
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	1,100
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	1,200
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	1,100
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	1,100
Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years	5,900
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 440	$ 553	$ 395
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	1.10%	1.50%
Swiss Plan [Member] | Debt Securities and Cash [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	47.00%
Swiss Plan [Member] | Real Estate Investments [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	25.00%
Swiss Plan [Member] | Alternative Investments [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	15.00%
Swiss Plan [Member] | Defined Benefit Plan, Equity Securities [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	13.00%
Post Age 65 Plan [Member] | Postretirement Health Coverage [Member]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	9.90%
Pre Age 65 Plan [Member] | Postretirement Health Coverage [Member]
Defined Benefit Plan, Health Care Cost Trend Rate, Annual Rate of Change	0.61%