Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenues, net of returns and allowances	$ 19,790	$ 14,460	$ 37,765	$ 35,152
Cost of sales	12,062	9,102	22,525	21,620
Gross profit	7,728	5,358	15,240	13,532
Selling, general and administrative	5,688	5,415	10,901	11,330
Research, development and engineering	1,869	915	3,114	1,537
Operating income (loss)	171	(972)	1,225	665
Loss on sale of subsidiary				(2,793)
Interest income (expense) and other, net	73	595	(182)	525
Income (loss) from continuing operations before income taxes	244	(377)	1,043	(1,603)
Income tax provision	490	166	570	207
(Loss) income from continuing operations, net of tax	(246)	(543)	473	(1,810)
Loss from discontinued operations, net of tax		(11,151)		(11,816)
Net (loss) income	$ (246)	$ (11,694)	$ 473	$ (13,626)
(Loss) Income Per Basic Share:
Basic (loss) income per share from continuing operations	$ (0.02)	$ (0.04)	$ 0.03	$ (0.13)
Basic loss per share from discontinued operations		(0.79)		(0.83)
Net (loss) income per basic share	(0.02)	(0.83)	0.03	(0.96)
(Loss) Income Per Diluted Share:
Diluted (loss) income per share from continuing operations	(0.02)	(0.04)	0.03	(0.13)
Diluted loss per share from discontinued operations		(0.79)		(0.83)
Net (loss) income per diluted share	$ (0.02)	$ (0.83)	$ 0.03	$ (0.96)
Weighted average shares outstanding - basic	14,151	14,150	14,121	14,193
Weighted average shares outstanding - diluted	14,151	14,150	14,217	14,193