Net Loss Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net loss attributable to common stockholders - basic	$ (91.4)	$ (66.4)	$ (234.1)	$ (171.0)
Net loss attributable to common stockholders - diluted	$ (91.4)	$ (66.4)	$ (234.1)	$ (171.0)
Denominator:
Weighted average common shares outstanding—basic (in shares)	66,877,100	61,580,145	63,482,945	61,086,238
Weighted average common shares outstanding—diluted (in shares)	66,877,100	61,580,145	63,482,945	61,086,238
Net loss per share attributable to common stockholders—basic (usd per share)	$ (1.37)	$ (1.08)	$ (3.69)	$ (2.80)
Net loss per share attributable to common stockholders—diluted (usd per share)	$ (1.37)	$ (1.08)	$ (3.69)	$ (2.80)