Note 1 - Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 26, 2021

Notes Tables

Schedule of Inventory, Current [Table Text Block]

	June 26,		December 26,
	2021		2020
Raw materials and purchased parts	$	89,037	$	83,755
Work in process		48,663		44,315
Finished goods		18,150		14,430
Total inventories	$	155,850	$	142,500

Property, Plant and Equipment [Table Text Block]

	June 26,			December 26,
	2021			2020
Land and land improvements	$	8,393		$	8,141
Buildings and building improvements		39,492			41,153
Machinery and equipment		60,402			65,342
		108,287			114,636
Less accumulated depreciation and amortization		(43,266	)		(47,720	)
Property, plant and equipment, net	$	65,021		$	66,916

Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Three Months Ended						Six Months Ended
	June 26,			June 27,			June 26,			June 27,
	2021			2020			2021			2020
Cost of sales	$	191		$	211		$	453		$	423
Research and development		763			828			1,544			1,661
Selling, general and administrative		2,552			2,364			5,032			4,930
Total share-based compensation		3,506			3,403			7,029			7,014
Income tax benefit		(180	)		(223	)		(414	)		(395	)
Total share-based compensation, net	$	3,326		$	3,180		$	6,615		$	6,619

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended				Six Months Ended
	June 26,		June 27,		June 26,		June 27,
	2021		2020		2021		2020
Weighted average common shares		48,555		41,844		46,155		41,673
Effect of dilutive securities		919		-		1,323		-
		49,474		41,844		47,478		41,673

Disaggregation of Revenue [Table Text Block]

	Three Months Ended				Six Months Ended
Disaggregated Net Sales	June 26, 2021		June 27, 2020		June 26, 2021		June 27, 2020
Systems:
Semiconductor Test & Inspection	$	149,661	$	74,011	$	287,820	$	144,550
PCB Test		9,211		8,109		17,831		14,949
Non-systems:
Semiconductor Test & Inspection		81,464		57,417		155,711		114,891
PCB Test		4,467		4,547		8,929		8,615
Total net sales	$	244,803	$	144,084	$	470,291	$	283,005

	Three Months Ended				Six Months Ended
Disaggregated Net Sales	June 26, 2021		June 27, 2020		June 26, 2021		June 27, 2020
China	$	57,183	$	31,133	$	111,448	$	61,944
Philippines		36,533		13,288		70,287		23,310
Taiwan		27,190		22,490		59,386		36,371
Malaysia		19,136		11,842		42,395		27,016
United States		21,878		20,550		41,937		39,628
Rest of the World		82,883		44,781		144,838		94,736
Total net sales	$	244,803	$	144,084	$	470,291	$	283,005

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	Three Months Ended				Six Months Ended
	June 26,		June 27,		June 26,		June 27,
	2021		2020		2021		2020
Semiconductor Test & Inspection
Customers individually accounting for more than 10% of net sales		*		*		*	one
Percentage of net sales		*		*		*		13%
PCB Test
Customers individually accounting for more than 10% of net sales		*		*		*		*
Percentage of net sales		*		*		*		*