Note 5 - Acquired Intangible Assets and Goodwill - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 25, 2021	Dec. 26, 2020
Balance	$ 32,695	$ 26,749
Acquisition	0	5,946
Balance	$ 32,695	$ 32,695

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
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-Section 55
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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 45
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant