Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 21,745	$ 18,623	$ 45,746	$ 42,659
Cost of revenue	15,936	13,676	34,129	29,798
Gross profit	5,809	4,947	11,617	12,861
Operating expense:
Selling, general, and administrative	6,996	5,644	14,589	10,463
Research and development	4,360	3,300	8,379	7,100
Gain from change in estimate on ARO obligation	(40)	0	(40)	0
(Gain) loss on sale of assets	0	(68)	0	39
Total operating expense	11,316	8,876	22,928	17,602
Operating loss	(5,507)	(3,929)	(11,311)	(4,741)
Other income:
Interest income, net	224	163	491	274
Foreign exchange gain	304	526	318	812
Total other income	528	689	809	1,086
Loss before income tax (expense) benefit	(4,979)	(3,240)	(10,502)	(3,655)
Income tax (expense) benefit	(15)	169	(30)	502
Net loss	(4,994)	(3,071)	(10,532)	(3,153)
Foreign exchange translation adjustment	13	121	27	374
Comprehensive (loss) income	$ (4,981)	$ (2,950)	$ (10,505)	$ (2,779)
Per share data:
Net loss per basic and diluted share (in usd per share)	$ (0.18)	$ (0.11)	$ (0.38)	$ (0.12)
Weighted-average number of basic and diluted shares outstanding (in shares)	27,652	27,197	27,592	27,113