Equity - Schedule of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income (loss)	$ 25,643	$ (7,000)	$ (35,984)
Denominator
Weighted average number of shares outstanding - basic (in shares)	34,020	29,136	27,983
Effect of dilutive securities
Weighted average number of shares outstanding - diluted (in shares)	35,789	29,136	27,983
Earnings (loss) per share - basic (in dollars per share)	$ 0.75	$ (0.24)	$ (1.29)
Earnings (loss) per share - diluted (in dollars per share)	$ 0.72	$ (0.24)	$ (1.29)
Weighted average antidilutive options, unvested restricted stock units and awards, unvested performance stock units and ESPP shares excluded from the computation (in shares)	195	1,109	810
Employee stock options
Effect of dilutive securities
Dilutive options outstanding, unvested stock units and unvested stock awards (in shares)	7	0	0
PSUs, RSUs, and restricted stock
Effect of dilutive securities
Dilutive options outstanding, unvested stock units and unvested stock awards (in shares)	1,762	0	0