Inventory (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Inventory Disclosure [Abstract]
Inventory write-down	$ 400	$ 3,100	$ 4,820	$ 5,345