Note 9 - Income Taxes (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended	12 Months Ended
	Feb. 26, 2021	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount				$ 5,100	$ 16,600
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability					$ (4,000)
Deferred Tax Assets, Valuation Allowance, Total		$ 86,124	$ 93,494
Increase (Decrease) of Net Income Due to Impact of Tax Holidays		$ 3,600	$ 2,100	$ 2,400
Increase (Decrease) of Earning Per Share Due To Impact Of Tax Holidays (in dollars per share)		$ 0.09	$ 0.05	$ 0.08
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		$ 5,700	$ 7,000	$ 8,200
Decrease in Unrecognized Tax Benefits is Reasonably Possible		600
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total		1,000	1,300
Unrecognized Tax Benefits, Interest Expense, Net of Accrued Interest Reversed		$ (300)	$ (300)	$ 600
Minimum [Member]
Collection Term Range (Year)		4 years
Maximum [Member]
Collection Term Range (Year)		10 years
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total		$ 200,900
Tax Credit Carryforward, Amount		$ 11,500
Open Tax Year		2016 2017 2018 2019 2020
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total		$ 130,100
Tax Credit Carryforward, Amount		$ 32,800
Open Tax Year		2015 2016 2017 2018 2019 2020
Foreign Tax Authority [Member]
Operating Loss Carryforwards, Total		$ 22,500
Foreign Tax Authority [Member] | Federal Ministry of Finance, Germany [Member]
Income Tax Examination, Year under Examination		2015 2016 2017
Foreign Tax Authority [Member] | Bureau of Internal Revenue, Philippines [Member]
Income Tax Examination, Year under Examination		2017
Foreign Tax Authority [Member] | Inland Revenue Board of Malaysia [Member] | Subsequent Event [Member]
Income Tax Examination, Year under Examination	2014 2015 2016 2017 2018 2019