Note 11 - Segment and Geographic Information - Summary of Current Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 29, 2025	Mar. 30, 2024
Net sales		$ 96,797	$ 107,614
Cost of sales	[1]	54,480	58,365
Research and development		23,152	22,336
Amortization of purchased intangible assets		9,852	9,795
Stock-based compensation		6,230	4,628
Loss before taxes		(25,966)	(16,335)
Semiconductor Test & Inspection Segment [Member]
Net sales		96,797	107,614
Cost of sales		54,155	58,138
Research and development		21,933	21,502
Selling		13,124	14,475
General & administrative		12,201	17,040
Amortization of purchased intangible assets		9,852	9,795
Stock-based compensation		6,230	4,628
Other segment items (1)	[2]	5,268	(1,629)
Loss before taxes		$ (25,966)	$ (16,335)

[1] Excludes amortization of purchased intangibles of $7,559 and $7,522 for the three months ended March 29, 2025 and March 30, 2024, respectively.

[2] Other segment items include restructuring charges as well as miscellaneous non-operating items.