Accounts receivable, net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Accounts receivable, net
Allowance for Doubtful Accounts Receivable, Current, Beginning Balance	$ 61	$ 115	$ 100	$ 88
Charge-offs	0	0	0	0
Recoveries	0	0
Provision for credit losses	12	(9)	40	18
Allowance for Doubtful Accounts Receivable, Current, Ending Balance	73	106	73	$ 106
Adoption of Accounting Standards Update 2016-13
Accounts receivable, net
Allowance for Doubtful Accounts Receivable, Current, Beginning Balance	$ 0	$ 0	$ (67)