Collaboration and License Agreements - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Revenue	$ 542,709	$ 0	$ 545,209	$ 3,551
GSK
Disaggregation of Revenue [Line Items]
Revenue	3	0	2,503	2,685
Takeda
Disaggregation of Revenue [Line Items]
Revenue	0	0	0	866
Sarepta
Disaggregation of Revenue [Line Items]
Revenue	$ 542,706	$ 0	$ 542,706	$ 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.

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details