Geographical Information (Schedule of Revenue by Geographic Region) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 17,717	$ 30,952	$ 60,376	$ 93,719
United States [Member]
Segment Reporting Information [Line Items]
Revenue	12,965	23,391	47,984	74,075
Asia [Member]
Segment Reporting Information [Line Items]
Revenue	3,116	5,699	7,919	14,190
Europe [Member]
Segment Reporting Information [Line Items]
Revenue	1,534	1,653	4,266	4,978
Other [Member]
Segment Reporting Information [Line Items]
Revenue	$ 102	$ 209	$ 207	$ 476