Cash, Cash Equivalents and Short-Term Investments - Schedule of Breakdown of the Short-Term Investments (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Less than 12 months
Fair Value	$ 114.6	$ 43.5
Gross Unrealized Losses	(0.5)	(0.2)
More than 12 months
Fair Value	350.0	534.8
Gross Unrealized Losses	(15.3)	(21.1)
Total
Fair Value	464.6	578.3
Gross Unrealized Losses	(15.8)	(21.3)
Corporate notes and obligations
Less than 12 months
Fair Value	77.6	25.1
Gross Unrealized Losses	(0.3)	(0.1)
More than 12 months
Fair Value	168.4	240.3
Gross Unrealized Losses	(7.4)	(10.2)
Total
Fair Value	246.0	265.4
Gross Unrealized Losses	(7.7)	(10.3)
U.S. Treasury securities
Less than 12 months
Fair Value	33.9	17.8
Gross Unrealized Losses	(0.2)	(0.1)
More than 12 months
Fair Value	92.2	174.0
Gross Unrealized Losses	(4.8)	(6.0)
Total
Fair Value	126.1	191.8
Gross Unrealized Losses	(5.0)	(6.1)
Asset backed securities
Less than 12 months
Fair Value	3.1	0.6
Gross Unrealized Losses	0.0	0.0
More than 12 months
Fair Value	46.0	66.0
Gross Unrealized Losses	(1.2)	(2.3)
Total
Fair Value	49.1	66.6
Gross Unrealized Losses	(1.2)	(2.3)
Municipal securities
Less than 12 months
Fair Value	0.0	0.0
Gross Unrealized Losses	0.0	0.0
More than 12 months
Fair Value	36.3	46.1
Gross Unrealized Losses	(1.4)	(2.0)
Total
Fair Value	36.3	46.1
Gross Unrealized Losses	(1.4)	(2.0)
U.S. agency obligations
Less than 12 months
Fair Value	0.0	0.0
Gross Unrealized Losses	0.0	0.0
More than 12 months
Fair Value	3.5	3.5
Gross Unrealized Losses	(0.3)	(0.3)
Total
Fair Value	3.5	3.5
Gross Unrealized Losses	(0.3)	(0.3)
Foreign government obligations
Less than 12 months
Fair Value	0.0	0.0
Gross Unrealized Losses	0.0	0.0
More than 12 months
Fair Value	1.9	3.3
Gross Unrealized Losses	(0.1)	(0.2)
Total
Fair Value	1.9	3.3
Gross Unrealized Losses	(0.1)	(0.2)
Supranational securities
Less than 12 months
Fair Value	0.0	0.0
Gross Unrealized Losses	0.0	0.0
More than 12 months
Fair Value	1.7	1.6
Gross Unrealized Losses	(0.1)	(0.1)
Total
Fair Value	1.7	1.6
Gross Unrealized Losses	$ (0.1)	$ (0.1)

Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions

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