Note 10 - Per Share Data - Unissued Shares of Common Stock Were Reserved for the Following Purposes (Details) - shares	Sep. 26, 2020	Dec. 28, 2019
Future grants of options or shares (in shares)	5,573	268,326
Shares reserved for employee stock purchase plan (in shares)	149,894	267,877
Total (in shares)	609,853	927,928
Time-based Restricted Stock Units [Member]
Restricted stock units outstanding (in shares)	454,386	151,725
Performance-based Restricted Stock Units [Member]
Restricted stock units outstanding (in shares)		240,000

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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+ References

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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