Acquisition, Discontinued Operations, Equity-Method Investment and Collaborative Arrangement - Collaborative Arrangements (Detail) - Collaborative Arrangement [Member] - Biohaven [Member] $ in Millions	Jan. 04, 2022 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment to collaborators	$ 500
Upfront payment to collaborators	150
Committed investment from collaborator	350
Collaborative arrangement, milestone payment upon commercializing (up to)	740
Acquired In-Process Research and Development Expense [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment and premium paid in equity investment	$ 263