Accounts receivable, net - (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Allowance for credit losses for accounts receivable:
Balances at beginning of the period	$ 131	$ 73	$ 147	$ 100
Provision (benefit) for credit losses	42	(10)	26	30
Balances at end of the period	$ 173	$ 63	$ 173	63
Adoption of Accounting Standards Update 2016-13
Allowance for credit losses for accounts receivable:
Balances at beginning of the period				$ (67)