Note 15 - Stock Plans - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Options outstanding at beginning of period (in shares)	6,860,701	7,373,951	6,393,876
Options outstanding at beginning of period (in dollars per share)	$ 3.40	$ 4.03	$ 4.78
Granted (in shares)	945,625	236,250	1,148,481
Granted (in dollars per share)	$ 2.25	$ 2.34	$ 1.95
Exercised (in shares)	30,250	48,250
Exercised (in dollars per share)	$ 2	$ 2.07
Forfeited (in shares)	50,000	452,375	51,125
Forfeited (in dollars per share)	$ 2.57	$ 5.85	$ 2.73
Expired (in shares)	761,750	248,875	117,281
Expired (in dollars per share)	$ 6.28	$ 16.68	$ 25.05
Options outstanding at end of period (in shares)	6,964,326	6,860,701	7,373,951
Options outstanding at end of period (in dollars per share)	$ 2.95	$ 3.40	$ 4.03
Options exercisable at end of period (in shares)	4,793,490	5,259,011	5,071,181