Revenue recognition (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		27 Months Ended
	Sep. 30, 2021	Dec. 31, 2019	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative
Contract assets			$ 0.2		$ 0.2	$ 0.6
Contract liabilities			2.8		2.8	1.4
Revenue recognized from customer contract liability			0.4	$ 1.0
KBI BioPharma, Inc. | Collaborative Arrangements
Collaborative Arrangement and Arrangement Other than Collaborative
Contract liabilities			0.9		0.9	$ 1.2
Upfront payment received					0.8
Aggregate milestone payments			2.8		2.8
Cumulative proceed from collaborative agreements			$ 2.3		$ 2.3
Contract term (years)	3 years	4 years
Collaborative arrangement, collaboration agreement fee	$ 0.3