Note 2 - Contract Liability (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 26, 2022	Mar. 27, 2021	Mar. 26, 2022	Mar. 27, 2021
Beginning Balance	$ 1,030	$ 1,716	$ 1,097	$ 1,327
Additions to contract liability	1,374	1,201	2,573	2,945
Amounts recognized as revenue	(1,312)	(1,827)	(2,578)	(3,182)
Ending Balance	$ 1,092	$ 1,090	$ 1,092	$ 1,090

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130549-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130532-203044

Name:	us-gaap_ContractWithCustomerLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant