Goodwill and Other Intangible Assets, Net - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Intangible Assets
Amortization of customer relationships, patents, non-competes and other intangibles	$ 50	$ 131	$ 155	$ 264
Total intangible assets, Gross Amount	6,191		6,191		$ 10,221
Finite-lived intangible assets, Accumulated Amortization	(807)		(807)		(4,682)
Carrying Amount	5,384		5,384		5,539
Patents
Intangible Assets
Finite-Lived Intangible Assets, Gross					4,030
Finite-lived intangible assets, Accumulated Amortization					(3,977)
Finite-lived intangible assets, Carrying Amount					53
Customer relationships
Intangible Assets
Finite-Lived Intangible Assets, Gross	2,100		2,100		2,100
Finite-lived intangible assets, Accumulated Amortization	(647)		(647)		(574)
Finite-lived intangible assets, Carrying Amount	1,453		1,453		1,526
Other Intangible Assets
Intangible Assets
Finite-Lived Intangible Assets, Gross	291		291		291
Finite-lived intangible assets, Accumulated Amortization	(160)		(160)		(131)
Finite-lived intangible assets, Carrying Amount	131		131		160
Trademarks
Intangible Assets
Indefinite-lived intangible assets	$ 3,800		$ 3,800		$ 3,800