Note 1 - Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 28, 2019

Notes Tables

Reclassification of Amounts on Income Statement [Table Text Block]

Three Months Ended September 29, 2018	As previously published		Amortization of purchased intangible assets			Foreign transaction gains (loss)			As adjusted
Cost of sales	$	51,786		(644	)		-		$	51,142
SG&A expense	$	16,511		(380	)		(232	)	$	15,899

Nine Months Ended September 29, 2018	As previously published		Amortization of purchased intangible assets			Foreign transaction gains (loss)		As adjusted
Cost of sales	$	165,701		(1,959	)		-	$	163,742
SG&A expense	$	50,926		(1,158	)		1,220	$	50,988

Schedule of Inventory, Current [Table Text Block]

	September 28,		December 29,
	2019		2018
Raw materials and purchased parts	$	70,677	$	60,112
Work in process		44,997		57,953
Finished goods		18,249		21,249
Total inventories	$	133,923	$	139,314

Property, Plant and Equipment [Table Text Block]

	September 28,			December 29,
	2019			2018
Land and land improvements	$	11,916		$	11,905
Buildings and building improvements		40,187			37,265
Machinery and equipment		63,451			64,791
		115,554			113,961
Less accumulated depreciation and amortization		(45,115	)		(39,629	)
Property, plant and equipment, net	$	70,439		$	74,332

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

	Three Months Ended						Nine Months Ended
	September 28,			September 29,			September 28,			September 29,
	2019			2018			2019			2018
Cost of sales	$	212		$	125		$	545		$	408
Research and development		820			354			2,234			1,098
Selling, general and administrative		2,474			1,401			8,082			3,991
Total share-based compensation		3,506			1,880			10,861			5,497
Income tax benefit		(67	)		(115	)		(426	)		(555	)
Total share-based compensation, net	$	3,439		$	1,765		$	10,435		$	4,942

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

	Three Months Ended				Nine Months Ended
	September 28,		September 29,		September 28,		September 29,
	2019		2018		2019		2018
Weighted average common shares		41,229		28,948		41,075		28,814
Effect of dilutive securities		-		822		-		836
		41,229		29,770		41,075		29,650

Disaggregation of Revenue [Table Text Block]

	Three Months Ended				Nine Months Ended
Net Sales (1)	September 28, 2019		September 29, 2018		September 28, 2019		September 29, 2018
Systems:
Semiconductor Test & Inspection	$	70,654	$	42,278	$	226,749	$	152,846
PCB Test		6,853		N/A		22,232		N/A
Non-systems:
Semiconductor Test & Inspection		62,166		43,886		180,343		128,285
PCB Test		3,825		N/A		11,994		N/A
Total net sales	$	143,498	$	86,164	$	441,318	$	281,131

	Three Months Ended				Nine Months Ended
Net Sales	September 28, 2019		September 29, 2018		September 28, 2019		September 29, 2018
China	$	31,076	$	23,628	$	87,365	$	63,011
United States		21,918		11,585		58,427		41,725
Taiwan		20,341		5,916		52,513		11,762
Malaysia		12,991		13,682		47,698		38,539
Philippines		12,330		11,158		38,266		31,620
Rest of the World		44,842		20,195		157,049		94,474
Total net sales	$	143,498	$	86,164	$	441,318	$	281,131

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

	Three Months Ended				Nine Months Ended
	September 28,		September 29,		September 28,		September 29,
	2019		2018		2019		2018
Semiconductor Test & Inspection (1)
Customers individually accounting for more than 10% of net sales		*		one		one		one
Percentage of net sales		*		11.2%		11.0%		10.8%
PCB Test
Customers individually accounting for more than 10% of net sales		*		N/A		*		N/A
Percentage of net sales		*		N/A		*		N/A