Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Loss Contingencies [Line Items]
Assessed penalty	$ 127
Rent expense	1,925	$ 1,313
Class Action Suit in Superior Court of California, Orange County - Wage-and-hour law violations
Loss Contingencies [Line Items]
Estimated loss on class action lawsuit	$ 385