Selected Quarterly Financial Information (unaudited) (Summary of Selected Quarter Financial Information) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting [Abstract]
Revenue	$ 29,176	$ 30,952	$ 32,591	$ 30,176	$ 25,600	$ 22,376	$ 21,532	$ 22,490	$ 122,895	$ 91,998	$ 81,685
Cost of revenue	18,565	20,110	21,553	20,133	16,481	14,964	14,510	15,089	80,361	61,044	52,994
Gross profit	10,611	10,842	11,038	10,043	9,119	7,412	7,022	7,401	42,534	30,954	28,691
Operating expense (income):
Selling, general, and administrative	5,181	5,815	5,672	5,578	4,963	6,125	4,825	4,821	22,246	20,734	24,711
Research and development	3,862	3,340	3,141	2,199	2,392	2,405	2,564	2,560	12,542	9,921	9,119
Impairments	38	0	468	0					506	0	0
Recovery of previously incurred litigation related fees and expenses from arbitration award					0	(2,599)	0	0	0	(2,599)	0
Gain from change in estimate on ARO obligation	(45)	0	0	0					(45)	0	(845)
Gain on sale of assets	(134)	(322)	0	0	0	(41)	0	0	(456)	(41)	228
Total operating expense	8,902	8,833	9,281	7,777	7,355	5,890	7,389	7,381	34,793	28,015	33,213
Operating income (loss)	1,709	2,009	1,757	2,266	1,764	1,522	(367)	20	7,741	2,939	(4,522)
Other income (expense):
Interest income, net	99	77	46	23	48	32	25	(17)	245	88	75
Foreign exchange gain (loss)	388	53	44	(403)	(83)	(201)	25	(135)	82	(394)	(138)
Other income	0	316	0	0					316	0	0
Total other income (expense)	487	446	90	(380)	(35)	(169)	50	(152)	643	(306)	59
Income (loss) from continuing operations before income tax expense	2,196	2,455	1,847	1,886	1,729	1,353	(317)	(132)	8,384	2,633	(4,463)
Income tax (expense) benefit	(32)	(19)	8	(120)	8	(175)	155	(2)	(163)	(14)	2,191	$ 24,600
Income (loss) from continuing operations	2,164	2,436	1,855	1,766	1,737	1,178	(162)	(134)	8,221	2,619	(2,272)
Income from discontinued operations, net of tax	41	(11)	(7)	(9)	259	123	4,144	1,121	14	5,647	65,372
Net income	$ 2,205	$ 2,425	$ 1,848	$ 1,757	$ 1,996	$ 1,301	$ 3,982	$ 987	$ 8,235	$ 8,266	$ 63,100
Net income per basic share:
Continuing operations (in usd per share)	$ 0.08	$ 0.09	$ 0.07	$ 0.07	$ 0.07	$ 0.05	$ (0.01)	$ 0.00	$ 0.31	$ 0.10	$ (0.08)
Discontinued operations (in usd per share)	0.00	0.00	0.00	0.00	0.01	0.00	0.16	0.04	0.00	0.22	2.18
Net income per basic share (in usd per share)	0.08	0.09	0.07	0.07	0.08	0.05	0.15	0.04	0.31	0.32	2.10
Net income per diluted share:
Continuing operations (in usd per share)	0.08	0.09	0.07	0.07	0.06	0.05	(0.01)	0.00	0.30	0.10	(0.08)
Discontinued operations (in usd per share)	0.00	0.00	0.00	0.00	0.01	0.00	0.16	0.04	0.00	0.21	2.18
Net income per diluted share (in usd per share)	$ 0.08	$ 0.09	$ 0.07	$ 0.07	$ 0.07	$ 0.05	$ 0.15	$ 0.04	$ 0.30	$ 0.31	$ 2.10
Weighted-average number of basic shares outstanding (in shares)	26,904	26,833	26,622	26,279	26,177	26,103	25,942	25,697	26,659	25,979	30,012
Weighted-average number of basic shares outstanding (in shares)	27,768	27,816	27,585	27,039	26,674	26,269	25,942	25,697	27,544	26,518	30,012