v3.24.1.u1
Cash, Cash Equivalents, and Short-term Investments - Components (Details) - USD ($)
$ in Millions
Mar. 31, 2024
Dec. 31, 2023
Mar. 31, 2023
Current assets:      
Cash $ 153.0 $ 201.9  
Cash equivalents:      
Unrealized Losses 0.0 0.0  
Amortized Cost 405.9 447.1  
Total cash and cash equivalents 405.9 447.1 $ 474.0
Short-term investments:      
Amortized Cost 34.3 82.2  
Unrealized Gains 0.0 0.0  
Unrealized Losses 0.0 0.0  
Estimated Fair Value 34.3 82.2  
Cash, cash equivalents, and short-term investments, amortized cost 440.2 529.3  
Cash, cash equivalents, and short-term investments, unrealized losses 0.0 0.0  
Total cash, cash equivalents, and short-term investments 440.2 529.3  
Money market mutual funds      
Cash equivalents:      
Amortized Cost 252.9 245.2  
Unrealized Losses 0.0 0.0  
Total cash equivalents 252.9 245.2  
Corporate debt securities      
Short-term investments:      
Amortized Cost 18.4 37.4  
Unrealized Gains 0.0 0.0  
Unrealized Losses 0.0 0.0  
Estimated Fair Value 18.4 37.4  
Securities guaranteed by U.S. government      
Short-term investments:      
Amortized Cost 4.7 26.7  
Unrealized Gains 0.0 0.0  
Unrealized Losses 0.0 0.0  
Estimated Fair Value 4.7 26.7  
Certificates of deposit      
Short-term investments:      
Amortized Cost 11.2    
Unrealized Gains 0.0    
Unrealized Losses 0.0    
Estimated Fair Value $ 11.2    
Other government securities      
Short-term investments:      
Amortized Cost   18.1  
Unrealized Gains   0.0  
Unrealized Losses   0.0  
Estimated Fair Value   $ 18.1