Summary of Revenue by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Schedule Of Revenues From External Customers [Line Items]
Revenue	$ 87,835	$ 95,809
Africa
Schedule Of Revenues From External Customers [Line Items]
Revenue	5,814	20,192
Asia
Schedule Of Revenues From External Customers [Line Items]
Revenue	41,128	10,171
Canada
Schedule Of Revenues From External Customers [Line Items]
Revenue	3,193	5,232
Europe
Schedule Of Revenues From External Customers [Line Items]
Revenue	12,626	25,860
United States
Schedule Of Revenues From External Customers [Line Items]
Revenue	23,780	32,397
Other
Schedule Of Revenues From External Customers [Line Items]
Revenue	$ 1,294	$ 1,957