Condensed Consolidated Statements of Operations and Comprehensive (Loss) Income - 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]
Revenue	$ 18,623	$ 32,591	$ 42,659	$ 62,767
Cost of revenue	13,676	21,553	29,798	41,686
Gross profit	4,947	11,038	12,861	21,081
Operating expense:
Selling, general, and administrative	5,644	5,672	10,463	11,250
Research and development	3,300	3,141	7,100	5,340
Impairments	0	468	0	468
(Gain) loss on sale of assets	(68)	0	39	0
Total operating expense	8,876	9,281	17,602	17,058
Operating (loss) income	(3,929)	1,757	(4,741)	4,023
Other income (expense):
Interest income, net	163	46	274	69
Foreign exchange gain (loss)	526	44	812	(359)
Total other income (expense)	689	90	1,086	(290)
(Loss) income from continuing operations before income tax benefit (expense)	(3,240)	1,847	(3,655)	3,733
Income tax benefit (expense)	169	8	502	(112)
(Loss) income from continuing operations	(3,071)	1,855	(3,153)	3,621
Loss from discontinued operations, net of tax	0	(7)	0	(16)
Net (loss) income	(3,071)	1,848	(3,153)	3,605
Foreign exchange translation adjustment	121	276	374	16
Comprehensive (loss) income	$ (2,950)	$ 2,124	$ (2,779)	$ 3,621
Net (loss) income per basic share:
Continuing operations (in usd per share)	$ (0.11)	$ 0.07	$ (0.12)	$ 0.14
Discontinued operations (in usd per share)	0.00	0.00	0.00	0.00
Net income per basic share (in usd per share)	(0.11)	0.07	(0.12)	0.14
Net (loss) income per diluted share:
Continuing operations (in usd per share)	(0.11)	0.07	(0.12)	0.13
Discontinued operations (in usd per share)	0.00	0.00	0.00	0.00
Net income per diluted share (in usd per share)	$ (0.11)	$ 0.07	$ (0.12)	$ 0.13
Weighted-average number of basic shares outstanding (in shares)	27,197	26,622	27,113	26,449
Weighted-average number of basic shares outstanding (in shares)	27,197	27,585	27,113	27,366