Acquisition - Fair value of the assets acquired and liabilities assumed (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 29, 2020	Dec. 31, 2019	Dec. 28, 2021
Business Acquisition [Line Items]
Goodwill.	$ 1,451		$ 1,451
Acquisition-related costs	$ 2,699	$ 5,270

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant