Revenue Recognition - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 21,906	$ 16,109	$ 59,572	$ 42,522
Deposits revenue
Disaggregation of Revenue [Line Items]
Total revenue	15,049	10,669	39,827	26,381
Identity verification revenue
Disaggregation of Revenue [Line Items]
Total revenue	6,857	5,440	19,745	16,141
Transferred at Point in Time | Deposits software and hardware
Disaggregation of Revenue [Line Items]
Total revenue	10,521	8,498	28,786	20,379
Transferred at Point in Time | Identity verification software and hardware
Disaggregation of Revenue [Line Items]
Total revenue	1,367	1,960	3,682	6,058
Transferred over Time | Deposits services and other
Disaggregation of Revenue [Line Items]
Total revenue	4,528	2,171	11,041	6,002
Transferred over Time | Identity verification services and other
Disaggregation of Revenue [Line Items]
Total revenue	$ 5,490	$ 3,480	$ 16,063	$ 10,083