Financial Instruments and Fair Value - Additional Information (Detail) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
|
Oct. 31, 2022
USD ($)
Security
|
Oct. 31, 2021
USD ($)
|
Oct. 31, 2022
USD ($)
Security
|
Oct. 31, 2021
USD ($)
|
|
| Investments Debt And Equity Securities [Abstract] | ||||
| Number of debt securities with unrealized losses for more than twelve months | Security | 0 | 0 | ||
| Interest income | $ 0.7 | $ 0.7 | $ 0.8 | $ 0.8 |
| Realized gains, net | $ 0.7 | $ 0.7 | $ 1.7 | $ 1.7 |