Net Loss Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net loss attributable to common stockholders - basic	$ (67.9)	$ (55.6)	$ (142.7)	$ (104.6)
Net loss attributable to common stockholders - diluted	$ (67.9)	$ (55.6)	$ (142.7)	$ (104.6)
Denominator:
Weighted average common shares outstanding—basic (in shares)	61,816,225	61,444,958	61,757,722	60,643,764
Weighted average common shares outstanding—diluted (in shares)	61,816,225	61,444,958	61,757,722	60,643,764
Net loss per share attributable to common stockholders—basic (usd per share)	$ (1.10)	$ (0.90)	$ (2.31)	$ (1.72)
Net loss per share attributable to common stockholders—diluted (usd per share)	$ (1.10)	$ (0.90)	$ (2.31)	$ (1.72)