Segment Information - Major customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Customer Revenues	$ 21,570	$ 20,044	$ 56,900	$ 53,278
Accounts Receivable | Customer Concentration Risk
Segment Reporting Information [Line Items]
% of Total Revenues			10.00%
Customer A | Sales Revenue, Net | Customer Concentration Risk
Segment Reporting Information [Line Items]
Customer Revenues	$ 1,900	$ 1,600	$ 3,400	$ 5,500
% of Total Revenues	9.00%	8.00%	6.00%	10.00%
Customer B | Sales Revenue, Net | Customer Concentration Risk
Segment Reporting Information [Line Items]
Customer Revenues	$ 3,000	$ 400	$ 5,000	$ 400
% of Total Revenues	14.00%	2.00%	9.00%	1.00%