Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Prepaid expenses and other current assets	$ 6,389	$ 6,098
Accrued expenses and other current liabilities	$ 14,521	7,573
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Prepaid expenses and other current assets		(6,600)
Accrued expenses and other current liabilities		$ (6,600)
Revenue From Products And Services Transferred Over Time Risk | Revenue Benchmark
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue from products and services transferred over time, as percentage of overall revenue (percentage)	100.00%	100.00%	100.00%
Transferred over time | Revenue From Products And Services Transferred Over Time Risk | Revenue Benchmark
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue from products and services transferred over time, as percentage of overall revenue (percentage)	4.00%	1.00%	1.00%