Property and equipment - Schedule of Right-of-Use Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Mar. 31, 2021
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation	$ (2,533)	$ (2,481)
Right of use property and equipment, net	5,508	6,093
Property
Property, Plant and Equipment [Line Items]
Right of use property and equipment, gross	7,821	8,348
Equipment, vehicles and other
Property, Plant and Equipment [Line Items]
Right of use property and equipment, gross	$ 220	$ 226