Collaborative and Other Relationships - Summary of Activity Related to the UCB Collaboration (Details) - Research and development - UCB Pharma S.A. - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Collaborative arrangements and non-collaborative arrangement transactions
Expense incurred by the collaboration	$ 13.6	$ 18.3	$ 46.2	$ 51.5
Expense reflected within statements of income	$ 6.8	$ 9.1	$ 23.1	$ 25.7