Income tax provision - Additional Information (Detail) - USD ($)	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Dec. 31, 2017	Oct. 31, 2017	Oct. 31, 2016
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		23.20%	35.00%	34.10%
Income Tax Expense (Benefit)		$ 1,468,000		$ 62,000
Provision For Income Tax Expense Percent		19.50%		26.90%
Unrecognized Tax Benefits		$ 59,000		$ 0	$ 0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense		6,000		$ 0
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		(41,000)
US federal and California [Member]
Income Taxes [Line Items]
Unrecognized Tax Benefits		$ 53,000
Scenario, Plan [Member]
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%