CONSOLIDATED STATEMENTS OF CHANGES IN CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Stockholders' Equity [Abstract]
Issuance costs	$ 22.8	$ 31.3
Issuance costs	$ 22.8	31.3
Exercise of stock options (in shares)	848,992
Issuance of common stock upon closing of Follow-on Offering, net of underwriting discounts and commissions and offering costs of $22.8 million	$ 640.3	338.0
Exercise of stock options	9.3	1.8	$ 0.5
Stock-based compensation	44.1	10.6	4.3
Net loss	(241.3)	(122.3)	(108.5)
Other comprehensive income	$ (5.2)	$ 1.7	$ 0.1
Common Stock
Issuance of common stock upon closing of initial public offering (in shares)	4,018,647	12,650,000
Exercise of stock options (in shares)	868,055	282,422	182,057
Additional Paid-In Capital
Issuance of common stock upon closing of Follow-on Offering, net of underwriting discounts and commissions and offering costs of $22.8 million	$ 640.3	$ 338.0
Exercise of stock options	9.3	1.8	$ 0.5
Stock-based compensation	44.1	10.6	4.3
Accumulated Deficit
Net loss	(241.3)	(122.3)	(108.5)
Accumulated Other Comprehensive Income
Other comprehensive income	$ (5.2)	$ 1.7	0.1
Series C Preferred Stock
Statement of Stockholders' Equity [Abstract]
Issuance costs			0.0
Issuance costs			0.0
Series D Preferred Stock
Statement of Stockholders' Equity [Abstract]
Issuance costs			0.6
Issuance costs			$ 0.6