Product Warranty Obligation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Product Warranties Disclosures [Abstract]
Warranty period, minimum			1 year
Warranty period, maximum			5 years
Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 1,164	$ 1,025	$ 987	$ 1,033
Warranties issued	362	62	716	231
Settlements made	(178)	(195)	(355)	(372)
Ending balance	$ 1,348	$ 892	$ 1,348	$ 892