Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands, € in Millions		3 Months Ended	12 Months Ended
	Oct. 01, 2019 USD ($)	Dec. 29, 2018 USD ($)	Dec. 28, 2019 USD ($) shares	Dec. 29, 2018 USD ($) shares	Dec. 30, 2017 USD ($) shares	Dec. 09, 2019 EUR (€)	Dec. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Number of VIEs Consolidated		1	1	1
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares			422,000	146,000	77,000
SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense			$ 4,800	$ 10,800	$ 1,100
Inventory Write-down		$ 19,100
Amount Committed to Acquire Leased Facility | €						€ 1.1
Depreciation, Total			19,300	8,800	5,000
Capitalized Computer Software, Gross			$ 10,300
Number of Operating Segments			4
Number of Reportable Segments			2
Goodwill and Intangible Asset Impairment, Total	$ 0
Revenue, Remaining Performance Obligation, Amount		19,100	$ 10,000	19,100
Contract with Customer, Liability, Total		10,800	16,100	10,800
Contract with Customer, Liability, Current		6,900	7,600	6,900
Contract with Customer, Liability, Noncurrent		2,000	7,200	2,000
Amortization of Debt Issuance Costs			1,100	1,100
Foreign Currency Transaction Gain (Loss), Realized				1,700	(3,000)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total		(25,880)	(34,030)	(25,880)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax			(7,500)	(8,900)
Operating Lease, Right-of-Use Asset			33,269
Assets, Total		1,134,002	1,077,710	1,134,002	$ 420,457
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption								$ 1,100
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset							$ 30,700
Operating Lease, Liability, Total							29,900
Sale Leaseback Transaction, Deferred Gain, Gross							(10,200)
Assets, Total							(500)
Liabilities, Total							$ (600)
Xcerra [Member]
Capital Leased Assets, Gross, Total		$ 2,700	$ 2,600	2,700
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
Xcerra [Member]
Inventory Write-down			$ 700	$ 9,400
ALBS [Member]
Variable Interest Entity, Ownership Percentage Sold			20.00%
Gain (Loss) on Disposition of Business			$ 100