License Agreements - Merus (Details) $ in Millions	1 Months Ended	12 Months Ended			97 Months Ended
	Dec. 31, 2016 USD ($) program	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2024 USD ($) shares
Merus
License agreements
Shares divested (in shares) | shares		4,000,000.0
Proceeds from sale of equity securities, FV-NI		$ 216.1
Investment owned (in shares) | shares		0			0
Equity securities, FV-NI			$ 110.1
Realized and unrealized gain (loss) on equity investments		$ 106.1	$ 45.2	$ (58.0)
Merus
License agreements
Number of independent programs | program	10
Number of programs under the resulting products are co-funded for development | program	2
Associated future global development costs from the initiation of a Phase IIb trial, if elected to co-develop	35.00%
Milestone payment made under license agreement					$ 10.0
Merus | United States
License agreements
Profit sharing	50.00%
Percentage of profit (losses)	50.00%
Merus | Minimum
License agreements
Royalty payments on future global net sales (as percent)	6.00%
Merus | Minimum | United States
License agreements
Royalty payments on future global net sales (as percent)	6.00%
Merus | Maximum
License agreements
Royalty payments on future global net sales (as percent)	10.00%
Percentage of reverse royalty	4.00%
Merus | Maximum | United States
License agreements
Royalty payments on future global net sales (as percent)	10.00%
Percentage of additional royalties	4.00%
Merus | Development and Regulatory Milestones | Maximum
License agreements
Additional milestone payments under the license agreement	$ 100.0
Merus | Commercialization Milestones | Maximum
License agreements
Additional milestone payments under the license agreement	$ 250.0