Summary of significant accounting policies - Potentially dilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Potentially dilutive securities
Total shares of common stock equivalents	5,933,046	2,968,232
Private Placement | Pre-funded Warrants
Potentially dilutive securities
Warrants to purchase of shares	1,813,734
Convertible preferred stock (as converted)
Potentially dilutive securities
Total shares of common stock equivalents	15,596	28,112
Employee Stock Option
Potentially dilutive securities
Total shares of common stock equivalents	811,121	715,620
Warrants to purchase common stock
Potentially dilutive securities
Total shares of common stock equivalents	5,075,321	2,194,788
Unvested restricted stock units
Potentially dilutive securities
Total shares of common stock equivalents	31,008	29,712