Debt - Settlement of debt (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	Aug. 31, 2022	May 31, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Debt Instrument [Line Items]
Cash Paid					$ 0.0	$ 1,000.0
Net Loss on Inducements and Settlements			$ 2.1	$ 85.2	$ 8.3	$ 85.5
2015 Senior Convertible Debt | Senior Convertible Debt | Long-term Debt
Debt Instrument [Line Items]
Principal Amount Settled	$ 22.0
Cash Paid	67.7
Net Loss on Inducements and Settlements	1.3
2017 Senior Convertible Debt | Senior Convertible Debt | Long-term Debt
Debt Instrument [Line Items]
Principal Amount Settled		$ 31.0
Cash Paid		65.3
Net Loss on Inducements and Settlements		5.9
2017 Senior Convertible Debt | Junior Convertible Debt | Long-term Debt
Debt Instrument [Line Items]
Principal Amount Settled	14.9
Cash Paid	29.2
Net Loss on Inducements and Settlements	$ 0.8
2017 Junior Convertible Debt | Junior Convertible Debt | Long-term Debt
Debt Instrument [Line Items]
Principal Amount Settled		3.6
Cash Paid		8.2
Net Loss on Inducements and Settlements		$ 0.3