Schedule of Accrued Warranty (Details) - USD ($)	12 Months Ended
Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Guarantees and Product Warranties [Abstract]
Balance, December 28, 2019	$ 509,000	$ 571,000	$ 649,000
Additions	435,000	471,000	159,000
Claims	(436,000)	(533,000)	(237,000)
Balance, September 26, 2020	$ 508,000	$ 509,000	$ 571,000

Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1),(c)(5)
-URI http://asc.fasb.org/extlink&oid=68068213&loc=d3e12565-110249

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