Net Loss per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net loss attributable to common stockholder—basic	$ (67.7)	$ (61.5)	$ (172.2)	$ (194.5)
Net loss attributable to common stockholders—diluted	$ (67.7)	$ (61.5)	$ (172.2)	$ (194.5)
Denominator:
Weighted average common shares outstanding—basic (in shares)	71,138,070	69,753,576	70,716,140	69,542,342
Weighted average common shares outstanding—diluted (in shares)	71,138,070	69,753,576	70,716,140	69,542,342
Net loss per share attributable to common stockholders—basic (usd per share)	$ (0.95)	$ (0.88)	$ (2.44)	$ (2.80)
Net loss per share attributable to common stockholders—diluted (usd per share)	$ (0.95)	$ (0.88)	$ (2.44)	$ (2.80)