Note 1 - Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 27, 2020

Notes Tables

Schedule of Inventory, Current [Table Text Block]

	June 27,		December 28,
	2020		2019
Raw materials and purchased parts	$	78,317	$	69,665
Work in process		45,978		46,591
Finished goods		17,516		14,450
Total inventories	$	141,811	$	130,706

Property, Plant and Equipment [Table Text Block]

	June 27,			December 28,
	2020			2019
Land and land improvements	$	8,724		$	11,659
Buildings and building improvements		42,467			41,474
Machinery and equipment		59,598			61,006
		110,789			114,139
Less accumulated depreciation and amortization		(44,984	)		(43,227	)
Property, plant and equipment, net	$	65,805		$	70,912

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

	Three Months Ended						Six Months Ended
	June 27,			June 29,			June 27,			June 29,
	2020			2019			2020			2019
Cost of sales	$	211		$	208		$	423		$	333
Research and development		828			776			1,661			1,414
Selling, general and administrative		2,364			2,678			4,930			5,608
Total share-based compensation		3,403			3,662			7,014			7,355
Income tax benefit		(223	)		(79	)		(395	)		(359	)
Total share-based compensation, net	$	3,180		$	3,583		$	6,619		$	6,996

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

	Three Months Ended				Six Months Ended
	June 27,		June 29,		June 27,		June 29,
	2020		2019		2020		2019
Weighted average common shares		41,844		41,125		41,673		40,999
Effect of dilutive securities		-		-		-		-
		41,844		41,125		41,673		40,999

Disaggregation of Revenue [Table Text Block]

	Three Months Ended				Six Months Ended
Disaggregated Net Sales	June 27, 2020		June 29, 2019		June 27, 2020		June 29, 2019
Systems:
Semiconductor Test & Inspection	$	74,011	$	76,155	$	144,550	$	156,095
PCB Test		8,109		8,407		14,949		15,379
Non-systems:
Semiconductor Test & Inspection		57,417		61,424		114,891		118,177
PCB Test		4,547		4,025		8,615		8,169
	$	144,084	$	150,011	$	283,005	$	297,820

	Three Months Ended				Six Months Ended
Disaggregated Net Sales	June 27, 2020		June 29, 2019		June 27, 2020		June 29, 2019
China	$	31,133	$	32,738	$	61,944	$	56,289
United States		20,550		19,408		39,628		36,509
Malaysia		11,842		16,993		27,016		34,707
Taiwan		22,490		17,202		36,371		32,172
Philippines		13,288		11,395		23,310		25,936
Rest of the World		44,781		52,275		94,736		112,207
Total net sales	$	144,084	$	150,011	$	283,005	$	297,820

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

	Three Months Ended		Six Months Ended
	June 27,	June 29,	June 27,	June 29,
	2020	2019	2020	2019
Semiconductor Test & Inspection
Customers individually accounting for more than 10% of net sales	*	one	one	one
Percentage of net sales	*	12%	13%	12%
PCB Test
Customers individually accounting for more than 10% of net sales	*	*	*	*
Percentage of net sales	*	*	*	*