Note 9 - Guarantees - Changes in Accrued Warranty (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Beginning balance	$ 4,350	$ 4,886	$ 5,848
Warranty accruals	6,765	6,088	6,747
Warranty payments	(6,316)	(6,624)	(7,709)
Warranty liability assumed	50
Ending balance	$ 4,849	$ 4,350	$ 4,886

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=68068213&loc=d3e12565-110249

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(5)
-URI http://asc.fasb.org/extlink&oid=68068213&loc=d3e12565-110249

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

Amount of increase in the standard and extended product warranty accrual from a business acquisition.

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- Definition

Amount of decrease in the standard and extended product warranty accrual from payments made in cash or in kind to satisfy claims under the terms of the standard and extended product warranty.

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Amount of increase in the standard and extended product warranty accrual from warranties issued.

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