Income Taxes (Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Statutory income tax amount	$ 1,890	$ 1,567	$ 2,341
State taxes, net of federal benefits	319	392	196
Transaction costs	60	143	0
Employee stock purchase plan	79	127	59
Foreign operations	556	431	225
Non-deductible executive compensation	150	115	171
Change in valuation allowance	(2,187)	173	520
Utilization of research and development tax credits	(3,116)	(2,881)	(2,173)
Deferred balance sheet remeasure	(952)	0	9
ASU 2016-09 excess stock compensation	(1,131)	(673)	(56)
Contingent consideration	1,212	(27)	250
Changes from provision to return	(458)	(111)	(511)
Adjustment of tax contingency reserves	329	151	146
U.S. deduction for foreign export sales	(630)	(355)	(146)
Global intangible low-taxed income	33	31	162
Other, net	178	(31)	(6)
Income tax (benefit) expense	(1,367)	(948)	1,187
Effective Income Tax Rate Reconciliation, Capital Loss Expiration	$ 2,301	$ 0	$ 0