Leases - Narrative (Details) ft² in Thousands, $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) ft² option	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Sep. 25, 2023 USD ($)
Lessee Lease Description [Line Items]
Short-term lease cost | $	$ 0.6	$ 0.0	$ 1.2
Corporate Headquarters In Pasadena | California
Lessee Lease Description [Line Items]
Office space leases (in sq ft) | ft²		49
Corporate Headquarters In Pasadena | California | Colorado Owner, LLC
Lessee Lease Description [Line Items]
Number of options to renew | option		1
Operating lease renewal term		5 years
Research Facility in San Diego | California
Lessee Lease Description [Line Items]
Office space leases (in sq ft) | ft²		144
Operating lease renewal term		10 years
Lease term		15 years
Maximum additional tenant improvement allowance | $		$ 7.2			$ 23.6
Additional tenant improvement allowance interest per annum		7.00%			9.00%
Additional tenant improvement allowance liability | $				$ 30.8
Research Facility in San Diego | California | Maximum
Lessee Lease Description [Line Items]
Number of options to renew | option		1
Research Facility in Madison | Wisconsin
Lessee Lease Description [Line Items]
Office space leases (in sq ft) | ft²		115
Number of options to renew | option		2
Operating lease renewal term		5 years