Income and Other Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income tax expense (benefit) computed at U.S. federal statutory rate	$ 5,506	$ (1,457)	$ (7,540)
State tax expense (benefit), net of U.S. federal effect	990	(156)	(906)
Foreign tax rate differential	24	13	(28)
Effect due to change in tax rate	0	(137)	(183)
Shortfall from stock based compensation	(122)	432	248
Other	103	94	223
Federal benefit on PPP loan forgiveness	(1,363)	0	0
Change in uncertain tax positions	(419)	0	0
State net operating loss carryforward adjustment	454	533	139
Change in valuation allowance	(4,601)	738	8,101
Total income tax expense	$ 572	$ 60	$ 54
Effective tax rate (percentage)	2.20%	0.90%	0.20%