Supporting Financial Information - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest expense	$ (297)	$ (192)	$ (485)	$ (619)
Amortization of deferred financing costs	(265)	(70)	(799)	(202)
Other income (expense), net	0	0	0	20
Interest expense, net	(562)	$ (262)	(1,284)	$ (801)
Write-off of remaining financing costs related to debt fully satisfied	$ 200		$ 600