Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands		3 Months Ended			12 Months Ended
	Oct. 01, 2018 USD ($)	Dec. 29, 2018 USD ($)	Dec. 29, 2018 USD ($)	Dec. 29, 2018 USD ($)	Dec. 29, 2018 USD ($)	Dec. 30, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2017 USD ($)
Number of VIEs Consolidated		1	1	1	1	0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares						77,000	697,000
Allowance for Doubtful Accounts Receivable, Current, Ending Balance		$ 300	$ 300	$ 300	$ 300	$ 200
SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense					10,800	1,100	$ 1,100
Inventory Write-down					9,400
Depreciation, Total					$ 8,850	4,987	3,509
Number of Operating Segments		4			4
Number of Reportable Segments		2		2	2
Goodwill and Intangible Asset Impairment, Total	$ 0
Contract with Customer, Liability, Total		$ 0	0	$ 0	$ 0	0	0
Contract with Customer, Liability, Current		10,800	10,800	10,800	10,800	10,400
Deferred Profit		6,896	6,896	6,896	6,896	6,608		$ 5,350
Deferred Profit Recognized After Year One		2,000	2,000	2,000	2,000
Amortization of Debt Issuance Costs					300
Foreign Currency Transaction Gain (Loss), Realized					1,700	(3,000)	2,600
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total		(25,880)	(25,880)	(25,880)	(25,880)	(17,787)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax					(8,900)	11,300
Capitalized Computer Software, Net, Ending Balance		2,900	2,900	2,900	2,900
Contract with Customer, Asset, Net, Total		0	0	0	0	0	$ 0
Non-current Other Accrued Liabilities [Member]
Deferred Profit Recognized After Year One						$ 800
Other Current Assets [Member]
Capitalized Computer Software, Net, Ending Balance		300	300	300	300
Other Noncurrent Assets [Member]
Capitalized Computer Software, Net, Ending Balance		2,600	2,600	2,600	2,600
Accounting Standards Update 2014-09 [Member]
Deferred Profit								(1,258)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption								$ 1,100
Xcerra [Member]
Inventory Write-down			19,100
Capital Leased Assets, Gross, Total		2,700	2,700	2,700	$ 2,700
Contract with Customer, Liability, Current	$ 1,500
Minimum [Member]
Standard Product Warranty Term					1 year
Maximum [Member]
Standard Product Warranty Term					3 years
Building [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life					30 years
Building [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life					40 years
Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life					5 years
Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life					15 years
Machinery, Equipment and Software [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life					3 years
Machinery, Equipment and Software [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life					10 years
ALBS [Member]
Variable Interest Entity, Consolidated, Assets, Pledged, Total		$ 0	$ 0	$ 0	$ 0