Significant accounting policies - Summary of Office, Administrative, and Travel Expense (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Oct. 31, 2021 |
Oct. 31, 2020 |
Oct. 31, 2019 |
|
| List Of Accounting Policies [Abstract] | |||
| Office and administrative | $ 316,401 | $ 355,361 | |
| Travel and entertainment | 160,332 | 137,943 | |
| Research and development, net | $ 3,148,871 | $ 476,733 | $ 493,304 |