Balance Sheet Accounts (Tables)

12 Months Ended

Sep. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Property, Plant and Equipment

The estimated useful lives of property, plant and equipment are as follows (in years):

	Estimated Useful Lives
Buildings	39
Research equipment	5
Manufacturing equipment	7 to 10
Furniture	7
Computers and software	3 to 5
Leasehold improvements	Shorter of asset life or lease term

The following table summarizes the Company’s major classes of property, plant and equipment:

	September 30,
	2025		2024
	(in thousands)
Land	$	2,996	$	2,996
Buildings	251,317		75,988
Research equipment	62,758		65,353
Manufacturing equipment	18,588		—
Furniture	5,594		5,594
Computers and software	1,064		981
Leasehold improvements	104,425		104,410
Construction in progress	15,942		188,731
	462,684		444,053
Less: Accumulated depreciation and amortization	(80,169)		(58,021)
Property, plant and equipment, net	$	382,515	$	386,032

Schedule of Accrued Expenses

Accrued expenses consisted of the following:

	September 30,
	2025		2024
	(in thousands)
Accrued research and development expenses	$	30,330	$	28,069
Accrued research and development expenses; co-development	31,296		23,351
Accrued capital expenditures	277		4,206
Accrued income taxes (benefits)	20,799		—
Other	7,717		7,391
Total accrued expenses	$	90,419	$	63,017