Consolidated Condensed Statements of Comprehensive Loss - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (115.3)	$ (51.6)	$ (338.7)	$ (348.8)
Other comprehensive income (loss):
Unrealized gain on available-for-sale securities, net of tax	0.0	0.0	0.0	0.8
Foreign currency translation loss	0.0	0.0	(0.1)	0.0
Total other comprehensive income (loss)	0.0	0.0	(0.1)	0.8
Comprehensive loss	$ (115.3)	$ (51.6)	$ (338.8)	$ (348.0)