Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 10,366	$ 8,411	$ 9,958
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	1,071	1,698	(2,003)
Change in net unrealized gain (loss) on investments	0	0	19
Less income tax (expense) benefit	0	0	(5)
Other comprehensive income (loss), net of tax	1,071	1,698	(1,989)
Comprehensive income	$ 11,437	$ 10,109	$ 7,969