Collaborative and Other Relationships - OCREVUS (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2024
OCREVUS
Collaborative arrangements and non-collaborative arrangement transactions
Royalty operating profit threshold for highest royalty rate percentage	$ 900.0
Reduction in royalty rate	50.00%
Collaboration agreement term	11 years
OCREVUS | Foreign Tax Authority
Collaborative arrangements and non-collaborative arrangement transactions
Royalty percentage to be received	3.00%
OCREVUS | Minimum
Collaborative arrangements and non-collaborative arrangement transactions
Royalty percentage to be received	13.50%
OCREVUS | Maximum
Collaborative arrangements and non-collaborative arrangement transactions
Royalty percentage to be received	24.00%
Mosunetuzumab
Collaborative arrangements and non-collaborative arrangement transactions
Percentage of future development costs		30.00%