Note 1 - Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 29, 2018

Notes Tables

Schedule of Inventory, Current [Table Text Block]

	September 29,		December 30,
	2018		2017
Raw materials and purchased parts	$	30,770	$	27,918
Work in process		24,210		25,130
Finished goods		8,844		9,037
Total inventories	$	63,824	$	62,085

Property, Plant and Equipment [Table Text Block]

	September 29,			December 30,
	2018			2017
Land and land improvements	$	7,855		$	8,017
Buildings and building improvements		14,038			13,779
Machinery and equipment		46,894			45,333
		68,787			67,129
Less accumulated depreciation and amortization		(35,865	)		(32,957	)
Property, plant and equipment, net	$	32,922		$	34,172

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three Months Ended						Nine Months Ended
	September 29,			September 30,			September 29,			September 30,
	2018			2017			2018			2017
Cost of sales	$	125		$	123		$	408		$	327
Research and development		354			278			1,098			856
Selling, general and administrative		1,401			1,459			3,991			4,153
Total share-based compensation		1,880			1,860			5,497			5,336
Income tax benefit		(115	)		(107	)		(555	)		(429	)
Total share-based compensation, net	$	1,765		$	1,753		$	4,942		$	4,907

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

	Three Months Ended				Nine Months Ended
	September 29,		September 30,		September 29,		September 30,
	2018		2017		2018		2017
Weighted average common shares		28,948		28,155		28,814		27,614
Effect of dilutive securities		822		950		836		1,026
		29,770		29,105		29,650		28,640

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

	Balance at		Adjustments			Balance at
	December 30,		due to adoption			December 31,
Financial Statement Line Item	2017		of ASC 606			2017
Deferred profit	$	6,608	$	(1,258	)	$	5,350
Income taxes payable	$	2,159	$	201		$	2,360
Retained earnings	$	150,726	$	1,057		$	151,783

	For the Three Months Ended September 29, 2018
			Balances
			without adoption		Effect of
Condensed Consolidated Statements of Income	As Reported		of ASC 606		Change
Net sales	$	86,164	$	86,820	$	(656	)
Income tax provision	$	2,302	$	2,421	$	(119	)
Net income	$	4,803	$	5,340	$	(537	)
Income per share:
Basic:	$	0.17	$	0.18	$	(0.01	)
Diluted:	$	0.16	$	0.18	$	(0.02	)

	For the Nine Months Ended September 29, 2018
			Balances
			without adoption		Effect of
Condensed Consolidated Statements of Income	As Reported		of ASC 606		Change
Net sales	$	281,131	$	279,038	$	2,093
Income tax provision	$	6,897	$	6,517	$	380
Net income	$	24,573	$	22,860	$	1,713
Income per share:
Basic:	$	0.85	$	0.79	$	0.06
Diluted:	$	0.83	$	0.77	$	0.06

			Balances
			without adoption		Effect of
Condensed Consolidated Balance Sheets*	As Reported		of ASC 606		Change
Deferred profit	$	1,894	$	5,396	$	(3,502	)
Retained earnings	$	171,110	$	168,339	$	2,771

Disaggregation of Revenue [Table Text Block]

	Three Months Ended		Nine Months Ended
	September 29, 2018		September 29, 2018
Systems	$	42,278	$	152,846
Non-systems		43,886		128,285
Net sales	$	86,164	$	281,131

	Three Months Ended		Nine Months Ended
	September 29, 2018		September 29, 2018
China	$	23,628	$	63,011
United States		11,585		41,725
Malaysia		13,682		38,539
Philippines		11,158		31,620
Rest of the World		26,111		106,236
Net sales	$	86,164	$	281,131

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

	Three Months Ended						Nine Months Ended
	September 29,			September 30,			September 29,			September 30,
	2018			2017			2018			2017
Customers individually accounting for more than 10% of net sales		one			two			one			two
Percentage of net sales		11.2	%		26.5	%		10.8	%		28.5	%