Supporting Financial Information - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest expense									$ (1,512)	$ (800)
Amortization of deferred financing costs									(982)	(275)
Other income (expense), net									21	(41)
Interest expense, net	$ (1,190)	$ (562)	$ (545)	$ (177)	$ (315)	$ (262)	$ (261)	$ (278)	$ (2,473)	$ (1,116)