Segment Information - Concentration of credit risk - Financing receivable (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Jun. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Financing receivables, net	$ 6,938	$ 7,306
Customer A | Financing Receivables | Credit Concentration Risk
Segment Reporting Information [Line Items]
Financing receivables, net	$ 1,500	$ 3,000
Concentration risk percentage	22.00%	41.00%
Customer B | Financing Receivables | Credit Concentration Risk
Segment Reporting Information [Line Items]
Financing receivables, net	$ 1,600	$ 1,900
Concentration risk percentage	23.00%	25.00%
Customer C | Financing Receivables | Credit Concentration Risk
Segment Reporting Information [Line Items]
Financing receivables, net	$ 1,100
Concentration risk percentage	16.00%
Customer D | Financing Receivables | Credit Concentration Risk
Segment Reporting Information [Line Items]
Financing receivables, net	$ 700
Concentration risk percentage	10.00%
Customer E | Financing Receivables | Credit Concentration Risk
Segment Reporting Information [Line Items]
Financing receivables, net	$ 300	$ 1,300
Concentration risk percentage	4.00%	18.00%