Stock-based compensation - Stock Options Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares
Number of options outstanding
Balance (in shares) | shares	15,387,546
Granted (in shares) | shares	0
Exercised (in shares) | shares	(2,329,067)
Forfeited (in shares) | shares	(1,019,743)
Expired (in shares) | shares	(388,956)
Balance (in shares) | shares	11,649,780	15,387,546
Options exercisable (in shares) | shares	9,809,565
Options unvested (in shares) | shares	1,840,072
Weighted  average  exercise  price  ($)
Balance (in usd per share) | $ / shares	$ 1.76
Granted (in usd per share) | $ / shares	0
Exercised (in usd per share) | $ / shares	0.81
Forfeited (in usd per share) | $ / shares	3.57
Expired (in usd per share) | $ / shares	2.36
Balance (in usd per share) | $ / shares	1.66	$ 1.76
Options exercisable (in usd per share) | $ / shares	1.24
Options unvested (in usd per share) | $ / shares	$ 3.89
Weighted average remaining contractual term (years)
Balance	7 years 3 months 25 days	7 years 1 month 13 days
Options exercisable	7 years 1 month 17 days
Options unvested	8 years 4 months 6 days
Aggregate intrinsic value ($)
Balance | $	$ 1,618	$ 8,763
Exercised | $	144
Options exercisable | $	1,438
Options unvested | $	$ 180