Stock-based compensation and equity transactions - Summary of status of options granted under stock option plans and changes in options outstanding (Detail) - Stock Option	3 Months Ended
	Jan. 31, 2019 $ / shares shares
Shares
Outstanding at November 1, 2018 | shares	942,366
Options granted | shares	93,000
Options exercised | shares	(65,734)
Options canceled or expired | shares	(5,250)
Options outstanding at January 31, 2019 | shares	964,382
Options exercisable at January 31, 2019 | shares	632,799
Options vested and expected to vest at January 31, 2019 | shares	963,022
Weighted Average Exercise Price
Outstanding at November 1, 2018 | $ / shares	$ 3.09
Options granted | $ / shares	8.47
Options exercised | $ / shares	5.20
Options canceled or expired | $ / shares	6.82
Options outstanding at January 31, 2019 | $ / shares	3.44
Options exercisable at January 31, 2019 | $ / shares	2.92
Options vested and expected to vest at January 31, 2019 | $ / shares	$ 3.45