Stock-Based Compensation - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 01, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)		4,600,465
Granted (in shares)		0		0
Number of options outstanding (in shares)		1,978,516	2,263,477
Stock-based compensation expense		$ 67,097	$ 78,130	$ 120,893
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award (in shares)		4,913,312	4,241,640
Stock-based compensation expense		$ 64,300	$ 69,700	113,600
Weighted average period to recognize pre-tax compensation expense		1 year 7 months 6 days
Unrecognized pre-tax compensation expense		$ 80,800
Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of options exercised		4,200	12,200	27,600
Stock-based compensation expense		2,800	$ 8,400	$ 10,800
Unrecognized pre-tax compensation expense		$ 100
Weighted average period to recognize pre-tax compensation expense		2 months
2013 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserve for issuance (in shares)		2,899,230
Number of shares forfeited (in shares)		159,678
Number of options outstanding (in shares)		1,290,720
2013 Plan | Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award (in shares)		1,608,510
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized (in shares)					8,000,000
Number of shares forfeited (in shares)		190,627
Granted (in shares)		3,749,840
Number of options outstanding (in shares)		32,151
2021 Plan | Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award (in shares)		2,768,776
Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized (in shares)		832,950
Common stock reserved for issuance (in shares)		510,600
Granted (in shares)		362,050
Number of options outstanding (in shares)		655,645
Inducement Plan | Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment award (in shares)		244,625
Visirna ESOP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized (in shares)	20,000,000
Granted (in shares)	7,500,000
Stock-based compensation expense		$ 6,900