Goodwill and intangible assets - Intangible Assets Balances (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2023	Sep. 30, 2022
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 66,130	$ 66,130
Accumulated amortization	(9,062)	(6,392)
Net book value	$ 57,068	$ 59,738
Developed Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average Amortization period in years	15 years	15 years
Gross carrying amount	$ 50,020	$ 50,020
Accumulated amortization	(6,005)	(4,375)
Net book value	$ 44,015	$ 45,645
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average Amortization period in years	11 years	11 years
Gross carrying amount	$ 15,210	$ 15,210
Accumulated amortization	(2,657)	(1,767)
Net book value	$ 12,553	$ 13,443
Tradenames & Trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average Amortization period in years	3 years	3 years
Gross carrying amount	$ 900	$ 900
Accumulated amortization	(400)	(250)
Net book value	$ 500	$ 650