Segment Information - Major customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Customer Revenues	$ 79,061	$ 72,916
Customer A
Segment Reporting Information [Line Items]
Customer Revenues	$ 3,800	$ 7,500
% of Total Revenues	5.00%	10.00%
Customer A | Accounts Receivable | Customer Concentration Risk
Segment Reporting Information [Line Items]
% of Total Revenues	1.00%	9.00%
Accounts receivable, gross	$ 300	$ 1,100
Customer B
Segment Reporting Information [Line Items]
Customer Revenues	$ 10,200	$ 1,100
% of Total Revenues	13.00%	3.00%
Customer B | Accounts Receivable | Customer Concentration Risk
Segment Reporting Information [Line Items]
% of Total Revenues	36.00%	2.00%
Accounts receivable, gross	$ 7,400	$ 200