Common stock - Stock for issuance (Details) - shares	Mar. 31, 2024	Dec. 31, 2023
Common stock
Stock options issued and outstanding under the Plans	8,531,683	7,978,291
Common stock warrants outstanding	157,314	500,000
Total reserved common stock	14,923,124	13,202,327
2020 Equity Incentive Plan
Common stock
Remaining shares available for issuance under the Plans and ESPP	5,327,876	4,250,303
ESPP
Common stock
Remaining shares available for issuance under the Plans and ESPP	906,251	473,733