Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Revenue	$ 122,895	$ 91,998	$ 81,685
Cost of revenue	80,361	61,044	52,994
Gross profit	42,534	30,954	28,691
Operating expense (income):
Selling, general, and administrative	22,246	20,734	24,711
Research and development	12,542	9,921	9,119
Impairments	506	0	0
Recovery of previously incurred litigation related fees and expenses from arbitration award	0	(2,599)	0
Gain from change in estimate on ARO obligation	(45)	0	(845)
(Gain) loss on sale of assets	(456)	(41)	228
Total operating expense	34,793	28,015	33,213
Operating income (loss)	7,741	2,939	(4,522)
Other income (expense):
Interest income, net	245	88	75
Foreign exchange gain (loss)	82	(394)	(138)
Change in fair value of financial instruments	0	0	122
Other income	316	0	0
Total other income (expense)	643	(306)	59
Income (loss) from continuing operations before income tax expense	8,384	2,633	(4,463)
Income tax (expense) benefit	(163)	(14)	2,191
Income (loss) from continuing operations	8,221	2,619	(2,272)
Income from discontinued operations, net of tax	14	5,647	65,372
Net income	8,235	8,266	63,100
Foreign exchange translation adjustment	(18)	(268)	(990)
Comprehensive income	$ 8,217	$ 7,998	$ 62,110
Net income (loss) per basic share:
Continuing operations (in usd per share)	$ 0.31	$ 0.10	$ (0.08)
Discontinued operations (in usd per share)	0.00	0.22	2.18
Net income per basic share (in usd per share)	0.31	0.32	2.10
Net income (loss) per diluted share:
Continuing operations (in usd per share)	0.30	0.10	(0.08)
Discontinued operations (in usd per share)	0.00	0.21	2.18
Net income per diluted share (in usd per share)	$ 0.30	$ 0.31	$ 2.10
Weighted-average number of basic shares outstanding (in shares)	26,659	25,979	30,012
Weighted-average number of basic shares outstanding (in shares)	27,544	26,518	30,012