Collaborative and Other Relationships - Summary of Activity Related To Denali Therapeutics (Details) - Research and development - Denali Therapeutics - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaborative arrangements and non-collaborative arrangement transactions
Expense incurred by the collaboration	$ 42.5	$ 14.6	$ 0.0
Expense reflected within statements of income	$ 25.5	$ 8.8	$ 0.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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