Stock option plan (Details) - Employee Stock Option [Member] - USD ($)		3 Months Ended		6 Months Ended
	Sep. 04, 2014	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Plan term	10 years
Vesting term	5 years
No. of Options Outstanding
Options outstanding beginning of period				243,900
Options granted during period	246,000
Options forfeited/cancelled during the period				(820)
Options outstanding end of period		243,080		243,080
Options expected to vest over term of grant		238,620		238,620
Options exercisable at end of period		48,680		48,680
Exercise Price
Options outstanding beginning of period				$ 18.45
Options granted during period	$ 18.45
Options forfeited/cancelled during period				$ 18.45
Options outstanding end of period		$ 18.45		$ 18.45
Compensation expense related to stock options		$ 23,000	$ 24,000	$ 47,000	$ 47,000
Unrecognized compensation cost		314,000		314,000
Aggregate intrinsic value of options expected to vest		608,481		608,481
Aggregate intrinsic value of options exercisable		$ 124,134		$ 124,134