Note 1 - Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2023	Dec. 31, 2022	Dec. 25, 2021
Net sales	$ 636,322	$ 812,775	$ 887,214
Semiconductor Test and Inspection [Member]
Net sales			860,454
PCB Test [Member]
Net sales			26,760
Systems [Member] | Semiconductor Test and Inspection [Member]
Net sales	326,448	474,655	541,589
Systems [Member] | PCB Test [Member]
Net sales	0	0	17,831
Non-systems [Member] | Semiconductor Test and Inspection [Member]
Net sales	309,874	338,120	318,865
Non-systems [Member] | PCB Test [Member]
Net sales	$ 0	$ 0	$ 8,929