Available-for-sale securities - Summary Of Investments (Details) - USD ($) $ in Thousands	Oct. 31, 2021	Jan. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 11,677	$ 11,989
Total available-for-sale securities	13,862	13,244
Gross Unrealized Gain/(Loss)	(2,185)	(1,255)
Convertible debt
Debt Securities, Available-for-sale [Line Items]
Fair Value	11,677	11,989
Total available-for-sale securities	13,862	13,244
Gross Unrealized Gain/(Loss)	$ (2,185)	$ (1,255)