Stock-Based Compensation - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Options
Outstanding at beginning of period (in shares)	4,178,194	4,408,274	4,408,274
Granted (in shares)	2,702,050	2,367,139
Exercised (in shares)	(379,425)	(1,264,899)
Cancelled (in shares)	(251,931)	(1,074,995)
Outstanding at end of period (in shares)	6,248,888	4,435,519	4,178,194	4,408,274
Vested at end of period (in shares)	2,607,444	2,807,686
Vested and expected to vest at end of period (in shares)	6,248,888	4,435,519
Weighted average exercise price
Outstanding at beginning of period (in dollars per share)	$ 2.98	$ 3.44	$ 3.44
Granted (in dollars per share)	2.94	1.10
Exercised (in dollars per share)	1.31	1.18
Cancelled (in dollars per share)	4.43	2.67
Outstanding at end of period (in dollars per share)	3.01	3.02	$ 2.98	$ 3.44
Vested at end of period (in dollars per share)	3.54	3.27
Vested and expected to vest at end of period (in dollars per share)	$ 3.01	$ 3.02
Weighted-average remaining contractual term and Aggregate intrinsic value
Outstanding at end of period (in years)	4 years 5 months 8 days	8 years 5 months 23 days	8 years 2 months 19 days	8 years 6 months 7 days
Vested at end of period (in years)		5 years 6 months 18 days
Vested and expected to vest at end of period (in years)	4 years 5 months 8 days	8 years 5 months 23 days
Outstanding at beginning of period (in dollars)	$ 11	$ 350	$ 350
Outstanding at end of period (in dollars)	2	25	$ 11	$ 350
Vested at end of period (in dollars)	0	22
Vested and expected to vest at end of period (in dollars)	$ 2	$ 25
Weighted average grant-date fair value of stock options granted	$ 2.00	$ 0.65