Nature of business and basis of presentation (Details) $ / shares in Units, $ in Millions	Feb. 10, 2023	May 16, 2022 USD ($) $ / shares shares	Mar. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 $ / shares
Common stock, par value (in dollars per share) | $ / shares			$ 0.001	$ 0.001
Reverse stock split ratio	0.05
Cash balance | $			$ 31.0
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
Number of shares to purchase under option		163,757
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