Deferred revenue - Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022
Contract with Customer, Liability [Roll Forward]
Beginning balance	$ 10,982	$ 17,965	$ 17,650	$ 14,095	$ 14,522
Revenue recognized					23,943
Revenue recognized	(9,877)	(9,143)	(4,507)	(7,016)
Increase	7,631	5,873	4,822	10,571	20,403
Ending balance	$ 8,736	$ 14,695	$ 17,965	$ 17,650	$ 10,982

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130531-203044

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130549-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130532-203044

Name:	us-gaap_ContractWithCustomerLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant