Revenue Recognition - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 25,413	$ 21,906	$ 70,672	$ 59,572
Deposits revenue
Disaggregation of Revenue [Line Items]
Total revenue	16,948	15,049	46,221	39,827
Identity verification revenue
Disaggregation of Revenue [Line Items]
Total revenue	8,465	6,857	24,451	19,745
Transferred at Point in Time | Deposits software and hardware
Disaggregation of Revenue [Line Items]
Total revenue	12,222	10,521	32,822	28,786
Transferred at Point in Time | Identity verification software and hardware
Disaggregation of Revenue [Line Items]
Total revenue	990	1,367	3,358	3,682
Transferred over Time | Deposits services and other
Disaggregation of Revenue [Line Items]
Total revenue	4,726	4,528	13,399	11,041
Transferred over Time | Identity verification services and other
Disaggregation of Revenue [Line Items]
Total revenue	$ 7,475	$ 5,490	$ 21,093	$ 16,063