Stock-based compensation and equity transactions - Summary of status of options granted under stock option plans and changes in options outstanding (Detail) - Stock Option	6 Months Ended
	Apr. 30, 2019 $ / shares shares
Shares
Outstanding at November 1, 2018 | shares	942,366
Options granted | shares	121,015
Options exercised | shares	(69,150)
Options canceled or expired | shares	(5,250)
Options outstanding at April 30, 2019 | shares	988,981
Options exercisable at April 30, 2019 | shares	698,815
Options vested and expected to vest at April 30, 2019 | shares	987,922
Weighted Average Exercise Price
Outstanding at November 1, 2018 | $ / shares	$ 3.09
Options granted | $ / shares	8.17
Options exercised | $ / shares	5.16
Options canceled or expired | $ / shares	6.82
Options outstanding at April 30, 2019 | $ / shares	3.55
Options exercisable at April 30, 2019 | $ / shares	3.19
Options vested and expected to vest at April 30, 2019 | $ / shares	$ 3.55