Income Taxes - Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current:
Federal	$ 0.0	$ 0.0	$ 0.0
State	0.0	0.0	0.0
Foreign	3.0	7.7	1.5
Total current	3.0	7.7	1.5
Deferred:
Federal	0.0	0.0	0.0
State	0.0	0.0	0.0
Foreign	0.0	0.0	0.0
Total deferred	0.0	0.0	0.0
Total income tax expense	$ 3.0	$ 7.7	$ 1.5