Income Taxes - Loss Before Income Taxes and Related Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income (loss) before income taxes:
Bermuda	$ (19,054)	$ (14,357)	$ (6,513)
Total loss before income taxes	(288,228)	(273,075)	(143,042)
Current taxes:
Bermuda	0	0	0
Total current tax expense	761	476	5
Deferred taxes:
Bermuda	0	0	0
Total deferred tax expense	0	0	208
Total income tax expense	761	476	213
United States
Income (loss) before income taxes:
Foreign	(29,509)	(11,246)	(7,229)
Current taxes:
Foreign	758	473	13
Deferred taxes:
Foreign	0	0	208
Switzerland
Income (loss) before income taxes:
Foreign	(239,666)	(247,445)	(129,261)
Current taxes:
Foreign	0	0	0
Deferred taxes:
Foreign	0	0	0
Other
Income (loss) before income taxes:
Foreign	1	(27)	(39)
Current taxes:
Foreign	3	3	(8)
Deferred taxes:
Foreign	$ 0	$ 0	$ 0