Income taxes - Summary of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Current tax
Domestic (South Africa)	$ (4,346)	$ (5,768)	$ (4,261)
Foreign federal	(74)	(165)	0
Foreign state	(517)	(1,020)	(978)
Total Current	(4,937)	(6,953)	(5,239)
Deferred tax
Domestic (South Africa)	573	3,987	(4,744)
Foreign federal	(155)	83	55
Foreign state	101	249	99
Total deferred	519	4,319	(4,590)
Total income tax expense	$ (4,418)	$ (2,634)	$ (9,829)