Organization and Summary of Significant Accounting Policies - Accounting Standards Update and Change in Accounting Principle (Details) - USD ($)	Mar. 31, 2022	Oct. 01, 2021	Sep. 30, 2021	Mar. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Principal	$ 316,250,000	$ 316,250,000
Unamortized debt discount		0
Deferred financing costs, net		(4,779,000)
Net carrying amount		311,471,000
Deferred tax asset	15,908,000	15,585,000	$ 9,746,000	$ 9,693,000
Deferred tax liability	179,000	(356,000)	3,684,000	167,000
Additional paid-in capital	341,913,000	339,049,000	403,312,000	399,439,000
Retained earnings	$ 384,246,000	$ 353,638,000	326,781,000	$ 327,798,000
As Reported September 30, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Principal			316,250,000
Unamortized debt discount			(48,785,000)
Deferred financing costs, net			(3,279,000)
Net carrying amount			264,186,000
Deferred tax asset			9,746,000
Deferred tax liability			3,684,000
Additional paid-in capital			403,312,000
Retained earnings			326,781,000
Adjustments | Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Principal			0
Unamortized debt discount			48,785,000
Deferred financing costs, net			(1,500,000)
Net carrying amount			47,285,000
Deferred tax asset			5,839,000
Deferred tax liability			(4,040,000)
Additional paid-in capital			(64,263,000)
Retained earnings			$ 26,857,000