Business acquisition - Change in contingent consideration (Details) - Abveris - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Dec. 31, 2021	Mar. 31, 2022
Business Combination, Contingent Consideration Arrangements, Change In Amount Of Contingent Consideration, Liability [Roll Forward]
Balance at December 1, 2021 – acquisition date	$ 20,664
Change in fair value during the period	(8,066)	$ 8,100
Balance at March 31, 2022	12,598
Contingent consideration
Business Combination, Contingent Consideration Arrangements, Change In Amount Of Contingent Consideration, Liability [Roll Forward]
Balance at December 1, 2021 – acquisition date	8,500
Change in fair value during the period	(2,800)
Balance at March 31, 2022	5,700
Holdbacks
Business Combination, Contingent Consideration Arrangements, Change In Amount Of Contingent Consideration, Liability [Roll Forward]
Balance at December 1, 2021 – acquisition date	12,164
Change in fair value during the period	(5,266)
Balance at March 31, 2022	$ 6,898