License and Collaboration Agreements - Schedule Of License and Royalty Revenue (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Other license and royalty revenue	$ 5,369	$ 12,936	$ 14,404
Total license and royalty revenue	470,347	154,567	35,233
Abb Vie Collaboration And License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalties on net sales of Zolgensma	370,000
Zolgensma Royalties [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalties on net sales of Zolgensma	$ 94,978	61,631	$ 20,829
Achievement Of Sales Based Milestone For Zolgensma [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Royalties on net sales of Zolgensma		$ 80,000