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Stock Incentive Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2026	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Nov. 13, 2023	Sep. 30, 2018	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total (in shares)		13,518,767		13,518,767
Stock‑based compensation expense		$ 2,083	$ 3,279	$ 4,506	$ 5,787
Weighted average grant date fair value of stock options (in dollars per share)		$ 4.80	$ 9.32	$ 5.23	$ 13.56
Outstanding Series A Preferred Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total (in shares)		3,362,644		3,362,644
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting term				4 years
Weighted average period				2 years 9 months 18 days
Granted (in shares)				420,650
Granted (in dollars per share)				$ 6.76
Estimated forfeitures rate				10.00%
Unrecognized compensation expense		$ 5,200		$ 5,200
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		$ 12,600		$ 12,600
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)	1,040,444
Total (in shares)		3,410,201		3,410,201
Employment Inducement Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for grants (in shares)		942,751		942,751
Total (in shares)		750,000		750,000			39,166
Old Cartesian Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for grants (in shares)		58,285		58,285
Award vesting term				4 years
Award expiration term				10 years
Unrecognized compensation expense related to unvested employee stock options						$ 2,600
Stock‑based compensation expense		$ 100	$ 200	$ 100	$ 400
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