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Stock Incentive Plans - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2024 shares	Jan. 31, 2024 shares	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares	Mar. 27, 2024	Dec. 31, 2023 shares	Nov. 13, 2023 USD ($) shares	Mar. 31, 2019 shares	Sep. 30, 2018 shares	Jun. 30, 2016 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total (in shares)			13,215,543		13,215,543
Stock‑based compensation expense \| $			$ 1,695	$ 2,321	$ 4,717	$ 8,380
Weighted average grant date fair value of stock options (in dollars per share) \| $ / shares			$ 14.23		$ 15.75	$ 26.89
Rounding down per-share exercise price (in shares)							33.333
Outstanding Series A Preferred Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total (in shares)			1,972,189		1,972,189
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting term					4 years
Weighted average period					3 years 2 months 12 days
Grants in period (in shares)					477,037
Grants in period (in dollars per share) \| $ / shares					$ 19.86
Estimated forfeitures rate					10.00%
Unrecognized compensation expense \| $			$ 5,800		$ 5,800
Common stock \| Outstanding Series A Preferred Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to unvested employee stock options \| $			$ 10,300		$ 10,300
Weighted average period					3 years
2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for grants (in shares)												40,341
Number of shares authorized, increase (in shares)	3,466,544	215,903
Total (in shares)			3,511,101		3,511,101
Employment Inducement Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for grants (in shares)			253,377		253,377
Total (in shares)	360,000							60,833		66,667	39,166
Old Cartesian Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for grants (in shares)			27,270		27,270
Award vesting term					4 years
Award expiration term					10 years
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)			0		0			14,112.299
Unrecognized compensation expense related to unvested employee stock options \| $									$ 2,600
Stock‑based compensation expense \| $			$ 300		$ 1,000
Old Cartesian Plan \| Old Cartestian \| Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)									776,865
Old Cartesian Plan \| Old Cartestian \| Preferred stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, number (in shares)									14,112.299