Licensing arrangements (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Product development and regulatory approval milestone payments		$ 2.9
Commercial milestone payments		2.8
Collaborative agreement, milestone payments made		0.0	$ 0.1
License Agreement with Purdue Research Foundation
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License Agreement, Maximum Aggregate Payment Payable		3.8
License Agreement with Purdue Research Foundation | Morphimmune Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License Agreement, upfront payment on execution		0.2
License Agreement, upfront payment on first and second anniversary		0.1
2021 Patent License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Certain regulatory, developmental, and commercial milestone payables	$ 2.2
License fee payment		$ 0.1	$ 0.1