Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($)			12 Months Ended
	Jun. 26, 2023	Jun. 02, 2020	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Principal			$ 297,500,000	$ 297,500,000
Unamortized discount			(2,777,000)	(3,796,000)
Deferred issuance costs			(12,817,000)	(17,753,000)
Total debt			281,906,000	275,951,000
Less: current portion of long-term debt			(87,094,000)
Total long-term debt			$ 194,812,000	$ 275,951,000
3.00% Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Maturity date		Jun. 01, 2025	Jun. 01, 2025	Jun. 01, 2025
Convertible debt coupon rate		3.00%	3.00%	3.00%
Effective interest rate			3.70%	3.70%
Principal		$ 175,000,000	$ 87,500,000	$ 87,500,000
Deferred issuance costs			(406,000)	(992,000)
Total debt			87,094,000	$ 86,508,000
Less: current portion of long-term debt			(87,094,000)
Total long-term debt			$ 74,121,000
1.50% Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Maturity date			Jul. 01, 2028	Jul. 01, 2028
Convertible debt coupon rate			1.50%	1.50%
Effective interest rate			8.55%	8.75%
Principal			$ 87,500,000	$ 87,500,000
Unamortized discount			(2,777,000)	(3,796,000)
Deferred issuance costs			(10,602,000)	(14,490,000)
Total debt			$ 74,121,000	$ 69,214,000
1.50% Convertible Senior Notes Due 2028
Debt Instrument [Line Items]
Maturity date	Jul. 01, 2028		Jul. 01, 2028	Jul. 01, 2028
Convertible debt coupon rate	1.50%		1.50%	1.50%
Effective interest rate			1.91%	1.91%
Principal	$ 190,000,000		$ 122,500,000	$ 122,500,000
Deferred issuance costs			(1,809,000)	(2,271,000)
Total debt			120,691,000	$ 120,229,000
Total long-term debt			$ 120,691,000