Net loss per share - Potentially dilutive securities were excluded from the calculation of diluted net loss per share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net loss per share
Potentially dilutive securities were excluded from the calculation of diluted net loss per share (in shares)	7,625,682	7,217,024
Employee Stock Option [Member]
Net loss per share
Potentially dilutive securities were excluded from the calculation of diluted net loss per share (in shares)	2,122,901	1,976,176
Restricted stock units
Net loss per share
Potentially dilutive securities were excluded from the calculation of diluted net loss per share (in shares)	426,392	160,660
2018 Notes.
Net loss per share
Potentially dilutive securities were excluded from the calculation of diluted net loss per share (in shares)		3,489
Employee Stock Purchase Plan
Net loss per share
Potentially dilutive securities were excluded from the calculation of diluted net loss per share (in shares)	6,486	6,796
Series A Preferred Stock
Net loss per share
Potentially dilutive securities were excluded from the calculation of diluted net loss per share (in shares)	833,333	833,333
Series B Preferred Stock
Net loss per share
Potentially dilutive securities were excluded from the calculation of diluted net loss per share (in shares)	4,236,570	4,236,570