Net Loss per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss attributable to common stockholders — basic	$ (202.2)	$ (236.9)	$ (297.8)
Net loss attributable to common stockholders — diluted	$ (202.2)	$ (236.9)	$ (297.8)
Denominator:
Weighted average common shares outstanding — basic (in shares)	71,023,115	69,658,912	64,921,524
Weighted average common shares outstanding — diluted (in shares)	71,023,115	69,658,912	64,921,524
Net loss per share attributable to common stockholders — basic (usd per share)	$ (2.85)	$ (3.40)	$ (4.59)
Net loss per share attributable to common stockholders — diluted (usd per share)	$ (2.85)	$ (3.40)	$ (4.59)