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Note 7 - Stock-based Compensation (Details Textual) - USD ($)		3 Months Ended		9 Months Ended
	Feb. 28, 2020	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)				$ 7.39	$ 7.96
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				3 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)				10 years
Share-based Payment Arrangement, Expense		$ 13,000	$ 58,000	$ 476,000	$ 496,000
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount		225,000		$ 225,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)				1 year 6 months 25 days
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expense		137,000	$ 124,000	$ 801,000	705,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)				1 year 5 months 15 days
Shares Granted, Value, Share-based Payment Arrangement, after Forfeiture, Total				$ 960,000	$ 763,000
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount		$ 534,000		$ 534,000
Restricted Stock Units (RSUs) [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				1 year
Restricted Stock Units (RSUs) [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				3 years
The 2015 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)	750,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)		790,000		790,000