REVENUE RECOGNITION - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 37,656	$ 43,070	$ 46,123	$ 45,703	$ 39,626	$ 39,195	$ 33,510	$ 32,473	$ 172,552	$ 144,804	$ 119,797
Deposits revenue
Disaggregation of Revenue [Line Items]
Revenue									104,134	86,561	75,517
Deposits software and hardware | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue									78,212	64,548	55,129
Deposits services and other | Transferred Over Time
Disaggregation of Revenue [Line Items]
Revenue									25,922	22,013	20,388
Identity verification revenue
Disaggregation of Revenue [Line Items]
Revenue									68,418	58,243	44,280
Identity verification software and hardware | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue									10,162	8,380	4,940
Identity verification services and other | Transferred Over Time
Disaggregation of Revenue [Line Items]
Revenue									$ 58,256	$ 49,863	$ 39,340