Basis of Presentation and Summary of Significant Accounting Policies - Deferred Profit (Details) $ in Thousands	Dec. 31, 2017 USD ($) systems equipment	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of similarly configured systems and processes | systems	2
Number of similarly configured items of equipment | equipment	2
Deferred revenues	$ 8,370		$ 6,822
Deferred costs	2,738		2,741
Deferred profit	$ 5,632	$ 4,081	$ 4,081