Note 9 - Stock Options - Options Outstanding (Details) - USD ($)	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Outstanding at beginning of year (in shares)	890,147	942,366
Outstanding at beginning of year, weighted average exercise price (in dollars per share)	$ 3.62	$ 3.09
Options granted (in shares)	140,241	124,097
Options granted, weighted average exercise price (in dollars per share)	$ 6.40	$ 8.16
Options exercised (in shares)	(241,209)	(171,066)
Options exercised, weighted average exercise price (in dollars per share)	$ 1.85	$ 3.86
Options canceled or expired (in shares)		(5,250)
Options canceled or expired, weighted average exercise price (in dollars per share)		$ 6.82
Options outstanding at end of year (in shares)	789,179	890,147
Options outstanding at end of year, weighted average exercise price (in dollars per share)	$ 4.66	$ 3.62
Options exercisable at end of year (in shares)	459,513	599,981
Options exercisable, weighted average exercise price (in dollars per share)	$ 4.48	$ 3.25
Options vested and expected to vest at end of year (in shares)	788,143	889,088
Options vested and expected to vest, weighted average exercise price (in dollars per share)	$ 4.67	$ 3.63
Option price range at end of year, lower limit (in dollars per share)	1.90	1.90
Option price range at end of year, upper limit (in dollars per share)	$ 8.69	$ 8.69
Aggregate intrinsic value of options exercised during year	$ 975,638	$ 317,827