Note 1 - Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 26, 2020

Notes Tables

Schedule of Inventory, Current [Table Text Block]

	September 26,		December 28,
	2020		2019
Raw materials and purchased parts	$	74,639	$	69,665
Work in process		47,936		46,591
Finished goods		15,304		14,450
Total inventories	$	137,879	$	130,706

Property, Plant and Equipment [Table Text Block]

	September 26,			December 28,
	2020			2019
Land and land improvements	$	7,881		$	11,659
Buildings and building improvements		41,624			41,474
Machinery and equipment		63,577			61,006
		113,082			114,139
Less accumulated depreciation and amortization		(48,536	)		(43,227	)
Property, plant and equipment, net	$	64,546		$	70,912

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

	Three Months Ended						Nine Months Ended
	September 26,			September 28,			September 26,			September 28,
	2020			2019			2020			2019
Cost of sales	$	218		$	212		$	641		$	545
Research and development		782			820			2,443			2,234
Selling, general and administrative		2,299			2,474			7,229			8,082
Total share-based compensation		3,299			3,506			10,313			10,861
Income tax benefit		(215	)		(67	)		(610	)		(426	)
Total share-based compensation, net	$	3,084		$	3,439		$	9,703		$	10,435

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

	Three Months Ended				Nine Months Ended
	September 26,		September 28,		September 26,		September 28,
	2020		2019		2020		2019
Weighted average common shares		41,947		41,229		41,764		41,075
Effect of dilutive securities		-		-		-		-
		41,947		41,229		41,764		41,075

Disaggregation of Revenue [Table Text Block]

	Three Months Ended				Nine Months Ended
Disaggregated Net Sales	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
Systems:
Semiconductor Test & Inspection	$	70,360	$	70,654	$	214,910	$	226,749
PCB Test		8,990		6,853		23,939		22,232
Non-systems:
Semiconductor Test & Inspection		66,865		62,166		181,756		180,343
PCB Test		4,432		3,825		13,047		11,994
	$	150,647	$	143,498	$	433,652	$	441,318

	Three Months Ended				Nine Months Ended
Disaggregated Net Sales	September 26, 2020		September 28, 2019		September 26, 2020		September 28, 2019
China	$	30,423	$	31,076	$	92,367	$	87,365
United States		32,111		21,918		71,739		58,427
Malaysia		11,435		12,991		38,451		47,698
Taiwan		22,689		20,341		59,060		52,513
Philippines		11,860		12,330		35,170		38,266
Rest of the World		42,129		44,842		136,865		157,049
Total net sales	$	150,647	$	143,498	$	433,652	$	441,318

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

	Three Months Ended				Nine Months Ended
	September 26,		September 28,		September 26,		September 28,
	2020		2019		2020		2019
Semiconductor Test & Inspection
Customers individually accounting for more than 10% of net sales		*		*		one		one
Percentage of net sales		*		*		11%		11%
PCB Test
Customers individually accounting for more than 10% of net sales		*		*		*		*
Percentage of net sales		*		*		*		*