Collaboration and License Agreements - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 146,267	$ 151,805	$ 208,813	$ 179,244
GSK
Disaggregation of Revenue [Line Items]
Revenue	30,000	120,000	29,323	120,000
Horizon
Disaggregation of Revenue [Line Items]
Revenue	0	7,918	21,667	14,585
Takeda
Disaggregation of Revenue [Line Items]
Revenue	116,156	20,821	132,468	41,593
Janssen
Disaggregation of Revenue [Line Items]
Revenue	111	3,066	355	3,066
Amgen
Disaggregation of Revenue [Line Items]
Revenue	$ 0	$ 0	$ 25,000	$ 0