Note 9 - Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Options outstanding, balance (in shares)	264	392		371
Weighted average exercise price per share (in dollars per share)	$ 29.25	$ 23.40		$ 20.81
Options outstanding, granted (in shares)	129	77	88
Weighted average exercise price per share, granted (in dollars per share)	$ 19.74	$ 34.84	$ 30.93
Options outstanding, exercised (in shares)	(5)	(196)	(67)
Weighted average exercise price per share, exercised (in dollars per share)	$ 23.95	$ 19.68	$ 19.05
Aggregate intrinsic value, exercised	$ 21	$ 3,866	$ 1,212
Options outstanding, Forfeited (in shares)		(9)
Weighted average exercise price per share, forfeited (in dollars per share)		$ 29.88
Options outstanding, balance (in shares)	388	264	392
Weighted average exercise price per share (in dollars per share)	$ 26.16	$ 29.25	$ 23.40
Contractual term - weighted average, balance (Year)	7 years 295 days
Aggregate intrinsic value, outstanding	$ 370
Options outstanding, vested and anticipated to vest in future (in shares)	384
Weighted average exercise price per share, vested and anticipated to vest in future (in dollars per share)	$ 26.17
Contractual term - weighted average, vested and anticipated to vest in future (Year)	7 years 288 days
Aggregate intrinsic value, vested and anticipated to vest in future	$ 366
Options outstanding, exercisable (in shares)	184
Weighted average exercise price per share, exercisable (in dollars per share)	$ 27.62
Contractual term - weighted average, exercisable (Year)	6 years 113 days
Aggregate intrinsic value, exercisable	$ 195
Minimum [Member]
Exercise price per share, balance, lower (in dollars per share)	$ 10.23	10.23	9.16	9.16
Exercise price per share, granted, lower (in dollars per share)	18.25	29.69	26.75
Exercise price per share, exercised, lower (in dollars per share)	18.05	9.16	9.16
Exercise price per share, forfeited, lower (in dollars per share)		23.95
Maximum [Member]
Exercise price per share, balance, upper (in dollars per share)	41.85	41.85	37.06	$ 34.49
Exercise price per share, granted, upper (in dollars per share)	21.57	41.85	37.06
Exercise price per share, exercised, upper (in dollars per share)	$ 26.75	37.06	$ 23.95
Exercise price per share, forfeited, upper (in dollars per share)		$ 37.06