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Stock-based Compensation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	21 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	0
Intrinsic value of stock options exercised	$ 4.5	$ 0.0
Fair value of options vested	$ 1.9	$ 0.2
2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)	36,588,278			36,588,278
Awards granted (in shares)	798,203
Stock options \| 2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years and in months)	4 years
Award expiration period (in years)	10 years
Stock options \| First Anniversary of Grant Date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years and in months)	1 year
Stock options \| First Anniversary of Grant Date \| 2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	25.00%
Stock options \| Monthly Vesting \| 2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years and in months)	36 months
Award vesting percentage	75.00%
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	0
Restricted Stock \| Share-based Payment Arrangement, Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years and in months)			4 years
Granted (in shares)				0
Restricted Stock \| First Anniversary of Grant Date \| Share-based Payment Arrangement, Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years and in months)			1 year
Award vesting percentage			25.00%
Restricted Stock \| Monthly Vesting \| Share-based Payment Arrangement, Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years and in months)			36 months
Award vesting percentage			75.00%