Summary of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Schedule Of Revenues From External Customers [Line Items]
Revenue	$ 20,587	$ 21,270	$ 19,247	$ 14,644	$ 23,683	$ 14,195	$ 20,558	$ 15,285	$ 75,748	$ 73,721	$ 62,060
Asia (excluding Middle East)
Schedule Of Revenues From External Customers [Line Items]
Revenue									2,143	7,924	18,745
Canada
Schedule Of Revenues From External Customers [Line Items]
Revenue									15,945	11,318	3,048
Europe
Schedule Of Revenues From External Customers [Line Items]
Revenue									4,743	3,883	4,219
Middle East
Schedule Of Revenues From External Customers [Line Items]
Revenue									76	609	1,749
United States
Schedule Of Revenues From External Customers [Line Items]
Revenue									50,522	47,966	32,317
Other
Schedule Of Revenues From External Customers [Line Items]
Revenue									$ 2,319	$ 2,021	$ 1,982