Summary of Revenue by Geographic Area (Details) - USD ($) $ 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
Schedule Of Revenues From External Customers [Line Items]
Revenue	$ 23,683	$ 14,195	$ 20,558	$ 15,285	$ 16,314	$ 17,678	$ 14,931	$ 13,137	$ 73,721	$ 62,060	$ 84,867
Asia (excluding Middle East)
Schedule Of Revenues From External Customers [Line Items]
Revenue									7,924	18,745	8,755
Canada
Schedule Of Revenues From External Customers [Line Items]
Revenue									11,318	3,048	2,298
Europe
Schedule Of Revenues From External Customers [Line Items]
Revenue									3,883	4,219	13,672
Middle East
Schedule Of Revenues From External Customers [Line Items]
Revenue									609	1,749	2,024
United States
Schedule Of Revenues From External Customers [Line Items]
Revenue									47,966	32,317	50,101
Other
Schedule Of Revenues From External Customers [Line Items]
Revenue									$ 2,021	$ 1,982	$ 8,017