Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 101,505	$ 104,680	$ 191,689	$ 215,021
Cost of goods sold	89,084	88,858	168,713	184,200
Gross profit	12,421	15,822	22,976	30,821
Selling, general and administrative expenses	16,073	15,994	32,288	31,692
Research and development expenses	1,636	1,623	3,294	3,092
Amortization of intangible assets	44	88	117	176
Restructuring and separation expenses	0	840	0	840
Operating loss	(5,332)	(2,723)	(12,723)	(4,979)
Other income	0	(507)	(507)	(1,015)
Interest expense	51	47	102	81
Interest income	(293)	(89)	(495)	(131)
Loss before income taxes	(5,090)	(2,174)	(11,823)	(3,914)
Income tax benefit	(1,760)	(1,345)	(2,831)	(2,786)
Net loss	$ (3,330)	$ (829)	$ (8,992)	$ (1,128)
Loss per share:
Basic (in dollars per share)	$ (0.29)	$ (0.07)	$ (0.78)	$ (0.10)
Diluted (in dollars per share)	$ (0.29)	$ (0.07)	$ (0.78)	$ (0.10)
Weighted average shares:
Basic (in shares)	11,509	11,445	11,503	11,441
Diluted (in shares)	11,509	11,445	11,503	11,441
Dividends per share (in dollars per share)	$ 0.26	$ 0.26	$ 0.52	$ 0.52