Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Effective Income Tax Rate Reconciliation, Amount
Income tax expense at Bermuda statutory rate	$ 0	$ 0	$ 0
Foreign rate differential	(25,720)	(37,622)	(40,056)
Impact of changes in enacted income tax rates	0	0	(27,150)
Currency remeasurement effects on Swiss deferred tax assets	(3,045)	(13,742)	0
Officer’s non-deductible share-based compensation	0	9,590	0
R&D tax credits	(2,819)	(3,771)	(1,208)
Share-based compensation deferral adjustment	0	(4,364)	4,089
Valuation allowance	36,331	50,333	65,193
Other	301	(88)	(107)
Total income tax expense	$ 5,048	$ 336	$ 761
Effective Income Tax Rate Reconciliation, Percent
Income tax expense at Bermuda statutory rate	0.00%	0.00%	0.00%
Foreign rate differential	12.80%	14.77%	13.90%
Impact of changes in enacted income tax rates	0.00%	0.00%	9.42%
Currency remeasurement effects on Swiss deferred tax assets	1.52%	5.39%	0.00%
Officer’s non-deductible share-based compensation	0.00%	(3.76%)	0.00%
R&D tax credits	1.40%	1.48%	0.42%
Share-based compensation deferral adjustment	0.00%	1.71%	(1.42%)
Valuation allowance	(18.08%)	(19.75%)	(22.62%)
Other	(0.15%)	0.03%	0.04%
Total income tax expense	(2.51%)	(0.13%)	(0.26%)