Debt - Interest Expense (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Debt Instrument [Line Items]
Net loss on extinguishment of debt	$ 3,500			$ 3,545	$ 0
Senior Notes | 2029 Convertible Notes
Debt Instrument [Line Items]
Contractual interest expense		$ 2,157	$ 0	4,744	0
Amortization of deferred financing costs		239	0	488	0
Total interest expense		2,396	0	5,232	0
Senior Notes | 2025 Convertible Notes
Debt Instrument [Line Items]
Contractual interest expense		614	1,025	2,170	3,073
Amortization of deferred financing costs		121	197	429	586
Net loss on extinguishment of debt		0	0	(5,389)	0
Total interest expense		735	1,222	(2,790)	3,659
Senior Notes | 2024 Convertible Notes
Debt Instrument [Line Items]
Contractual interest expense		247	1,033	1,370	3,099
Amortization of deferred financing costs		39	156	218	465
Net loss on extinguishment of debt		0	0	8,935	0
Total interest expense		$ 286	$ 1,189	$ 10,523	$ 3,564