Income Taxes (Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Statutory income tax amount	$ 1,567	$ 2,341	$ 809
State taxes, net of federal benefits	392	196	(71)
Manufacturing deduction	0	0	(364)
Transaction costs	143	0	79
Employee stock purchase plan	127	59	56
Foreign operations	431	225	318
Non-deductible executive compensation	115	171	27
Change in valuation allowance	173	520	(994)
Utilization of research and development tax credits	(2,881)	(2,173)	(1,971)
One-time transition tax	0	0	250
Deferred balance sheet remeasure	0	9	2,727
ASU 2016-09 excess stock compensation	(673)	(56)	643
Contingent consideration	(27)	250	388
Changes from provision to return	(111)	(511)	(554)
Adjustment of tax contingency reserves	151	146	193
U.S. deduction for foreign export sales	(355)	(146)	0
Global intangible low-taxed income	31	162	0
Other, net	(31)	(6)	83
Income tax (benefit) expense	$ (948)	$ 1,187	$ 1,619