Nature of business and basis of presentation (Details) $ / shares in Units, $ in Millions	May 16, 2022 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares	Dec. 31, 2021 $ / shares
Common stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Cash balance | $		$ 28.8
Atrin Pharmaceuticals, Inc
Number of shares to purchase under option	163,757
Common Stock | Atrin Pharmaceuticals, Inc
Issuance of stock upon acquisition of Atrin (in shares)	55,869
Common stock, par value (in dollars per share) | $ / shares	$ 0.001
Series A Convertible Preferred Stock | Atrin Pharmaceuticals, Inc
Issuance of stock upon acquisition of Atrin (in shares)	2,949,630
Conversion value | $	$ 68.8
Preferred stock conversion ratio	10