Stockholders' Equity - Summary of Antidilutive Securities Excluded From Calculation (Details) - shares shares in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Antidilutive securities excluded from computation of diluted weighted average shares (in shares)	2,032	1,746	4,163
Restricted stock units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Antidilutive securities excluded from computation of diluted weighted average shares (in shares)	598	219	232
Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Antidilutive securities excluded from computation of diluted weighted average shares (in shares)	4	0	0
Class B Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Antidilutive securities excluded from computation of diluted weighted average shares (in shares)	1,430	1,527	3,931