Collaboration and License Agreements - Glaxosmithkline Intellectual Property (No. 3) Limited (Details) $ in Thousands		12 Months Ended
	Nov. 22, 2021 USD ($) bundle obligation	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2023 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		$ 240,735	$ 243,231	$ 138,287
GSK | Collaboration and License agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of distinct performance obligations | obligation	1
Number of distinct bundle | bundle	1
Initial transaction price	$ 120,000
Milestone payment receivable					$ 30,000
Milestone payment receivable upon achievement of phase two and first patient dosed in phase three	100,000
Revenue		$ 300	$ 4,800
GSK | Collaboration and License agreements | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Commercial milestone payments at first commercial sale	190,000
Sales-related milestone payments	$ 590,000