Development expenditure (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Costs capitalized	$ 985	$ 647	$ 1,956	$ 1,383
Costs expensed	1,314	1,046	2,751	2,040
Total costs incurred	$ 2,299	$ 1,693	$ 4,707	$ 3,423
Percentage capitalized	42.80%	38.20%	41.60%	40.40%