CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative-effect adjustment for adoption of ASC 842	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Deficit Cumulative-effect adjustment for adoption of ASC 842
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Beginning Balance (shares) at Sep. 30, 2019			12,036	0
Beginning Balance at Sep. 30, 2019	$ 45,571	$ (2)	$ 12	$ 0	$ 85,114	$ (39,555)	$ (2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Expense related to director restricted stock unit (shares)			90
Expense related to director restricted stock units	347				347
Expense related to employee stock options	563				563
Exercise of stock options (shares)			395
Exercise of stock options	55				55
Repurchases of common stock (in shares)				28
Repurchases of common stock	(113)			$ (113)
Cancellation of common stock (in shares)			(117)	(28)
Cancellation of common stock	(98)			$ 113	(211)
Net income	$ 7,114					7,114
Ending Balance (shares) at Sep. 30, 2020	12,404		12,404	0
Ending Balance at Sep. 30, 2020	$ 53,437		$ 12	$ 0	85,868	(32,443)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Expense related to director restricted stock unit (shares)			141
Expense related to director restricted stock units	467				467
Expense related to employee stock options	$ 1,193				1,193
Exercise of stock options (shares)	175		175
Exercise of stock options	$ 434		$ 1		433
Repurchases of common stock	0
Cancellation of common stock (in shares)			(6)
Cancellation of common stock	(68)				(68)
Net income	$ 10,145					10,145
Ending Balance (shares) at Sep. 30, 2021	12,404		12,714	0
Ending Balance at Sep. 30, 2021	$ 65,608		$ 13	$ 0	$ 87,893	$ (22,298)