Note 6 - Stock-based Compensation - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Jun. 29, 2019 USD ($) $ / shares shares
Options outstanding, balance (in shares) | shares	264
Weighted average exercise price per share, (in dollars per share)	$ 29.25
Options outstanding, granted (in shares) | shares	58
Weighted average exercise price per share, granted (in dollars per share)	$ 21.57
Options outstanding, exercised (in shares) | shares	(5)
Weighted average exercise price per share, exercised (in dollars per share)	$ 23.95
Exercised | $	$ 21
Options outstanding, balance (in shares) | shares	317
Weighted average exercise price per share (in dollars per share)	$ 27.93
Contractual term - weighted average, balance (Year)	7 years 215 days
Aggregate intrinsic value, balance | $	$ 200
Options outstanding, vested and anticipated to vest in future (in shares) | shares	313
Weighted average exercise price per share, vested and anticipated to vest in future (in dollars per share)	$ 27.91
Contractual term - weighted average, vested and anticipated to vest in future (Year)	7 years 208 days
Aggregate intrinsic value, vested and anticipated to vest in future | $	$ 200
Options outstanding, exercisable (in shares) | shares	145
Weighted average exercise price per share, exercisable (in dollars per share)	$ 26.05
Contractual term - weighted average, exercisable (Year)	6 years 51 days
Aggregate intrinsic value, exercisable | $	$ 200
Minimum [Member]
Exercise price per share, balance, lower (in dollars per share)	$ 10.23
Exercise price per share, granted, lower (in dollars per share)	21.57
Exercise price per share, exercised, lower (in dollars per share)	18.05
Maximum [Member]
Exercise price per share, balance, upper (in dollars per share)	41.85
Exercise price per share, granted, upper (in dollars per share)	21.57
Exercise price per share, exercised, upper (in dollars per share)	$ 26.75