Net Loss Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net loss attributable to common stockholders	$ (49.0)	$ (36.5)
Denominator:
Weighted average common shares outstanding—basic (shares)	60,218,652	11,542,042
Weighted average common shares outstanding—diluted (shares)	60,218,652	11,542,042
Net loss per share attributable to common stockholders—basic (usd per share)	$ (0.81)	$ (3.16)
Net loss per share attributable to common stockholders—diluted (usd per share)	$ (0.81)	$ (3.16)