Note 6 - Employee Benefit Plans - Benefit Obligation, Fair Value of Plan Assets, Funded Status and Liability of Swiss Plan (Details) - Swiss Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2024	Dec. 30, 2023	Dec. 31, 2022
Benefit obligation at beginning of year	$ (24,884)	$ (21,628)
Service cost	(643)	(551)	$ (954)
Interest cost	(357)	(510)	(56)
Actuarial gain (loss)	79	(1,391)
Participant contributions	(988)	(1,153)
Benefits paid	599	385
Plan change	203	0
Settlements	2,820	2,177
Foreign currency exchange adjustment	1,660	(2,213)
Benefit obligation at end of year	(21,511)	(24,884)	(21,628)
Fair value of plan assets at beginning of year	19,700	18,411
Return on assets, net of actuarial loss	732	52
Employer contributions	783	860
Participant contributions	988	1,153
Benefits paid	(599)	(385)
Settlements	(2,820)	(2,177)
Foreign currency exchange adjustment	(1,326)	1,786
Fair value of plan assets at end of year	17,458	19,700	$ 18,411
Net liability at end of year	$ (4,053)	$ (5,184)