Acquisitions (Asset Acquisitions) (Details) - USD ($)	1 Months Ended									3 Months Ended		9 Months Ended
	Sep. 30, 2021	Aug. 31, 2021	Jul. 31, 2021	May 31, 2021	Mar. 31, 2021	Jan. 31, 2021	Jun. 30, 2020	May 31, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Business Acquisition [Line Items]
Acquired IPR&D Expense										$ 174,000,000	$ 0	$ 498,300,000	$ 294,100,000
Precision Biosciences, Inc.
Business Acquisition [Line Items]
Acquired IPR&D Expense						$ 107,800,000
Merus N.V.
Business Acquisition [Line Items]
Acquired IPR&D Expense						46,500,000
Asahi Kasei Pharma Corporation
Business Acquisition [Line Items]
Acquired IPR&D Expense						$ 20,000,000.0
Rigel Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Acquired IPR&D Expense					$ 125,000,000.0
MiNA Therapeutics Limited
Business Acquisition [Line Items]
Acquired IPR&D Expense				$ 25,000,000.0
Protomer Technologies Inc.
Business Acquisition [Line Items]
Acquired IPR&D Expense			$ 57,300,000
Kumquat Biosciences Inc.
Business Acquisition [Line Items]
Acquired IPR&D Expense			$ 55,000,000.0
Lycia Therapeutics, Inc.
Business Acquisition [Line Items]
Acquired IPR&D Expense		$ 35,000,000.0
ProQR Therapeutics N.V.
Business Acquisition [Line Items]
Acquired IPR&D Expense	$ 26,700,000
Sitryx Therapeutics Limited
Business Acquisition [Line Items]
Acquired IPR&D Expense									$ 52,300,000
AbCellera
Business Acquisition [Line Items]
Acquired IPR&D Expense								$ 25,000,000	$ 25,000,000.0
Junshi Biosciences
Business Acquisition [Line Items]
Acquired IPR&D Expense								20,000,000.0
Petra
Business Acquisition [Line Items]
Acquired IPR&D Expense								$ 174,800,000
Evox Therapeutics Limited
Business Acquisition [Line Items]
Acquired IPR&D Expense							$ 22,000,000.0