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Description of the Business (Details) $ / shares in Units, $ in Thousands						3 Months Ended
	Jul. 02, 2024 USD ($) $ / shares shares	Apr. 04, 2024	Mar. 27, 2024	Dec. 06, 2023	Nov. 13, 2023 USD ($) $ / shares shares	Mar. 31, 2025 USD ($) $ / shares	Dec. 31, 2024 USD ($) $ / shares
Cash and Cash Equivalents [Line Items]
Common stock, par value (in dollars per share) | $ / shares					$ 0.0001	$ 0.0001	$ 0.0001
Temporary equity, par value (in dollars per share) | $ / shares					$ 0.0001
Reverse stock split conversion ratio		0.0333
Cash, cash equivalents, restricted cash and marketable securities | $						$ 182,100
Restricted cash and cash equivalents | $						1,700
Accumulated deficit | $						$ 709,781	$ 692,071
Minimum
Cash and Cash Equivalents [Line Items]
Reverse stock split conversion ratio			0.05
Maximum
Cash and Cash Equivalents [Line Items]
Reverse stock split conversion ratio			0.0333
Securities Purchase Agreement
Cash and Cash Equivalents [Line Items]
Sale of stock, number of shares issued in transaction (in shares) | shares					149,330.115
Total aggregate purchase price | $					$ 60,250
July 2024 Purchase Agreement
Cash and Cash Equivalents [Line Items]
Sale of stock, price per share (in dollars per share) | $ / shares	$ 20.00
Sale of stock, gross consideration received on transaction | $	$ 130,000
Common stock | July 2024 Purchase Agreement
Cash and Cash Equivalents [Line Items]
Sale of stock, number of shares issued in transaction (in shares) | shares	3,563,247
Series B Preferred Stock
Cash and Cash Equivalents [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001
Series B Preferred Stock | July 2024 Purchase Agreement
Cash and Cash Equivalents [Line Items]
Sale of stock, number of shares issued in transaction (in shares) | shares	2,937,903
Old Cartesian
Cash and Cash Equivalents [Line Items]
Contingent value right, percentage of milestone payments, royalties and other amounts to be distributed				100.00%		100.00%
Old Cartesian | Common stock
Cash and Cash Equivalents [Line Items]
Issuance of shares (in shares) | shares					224,099
Old Cartesian | Preferred stock | Series A Preferred Stock
Cash and Cash Equivalents [Line Items]
Issuance of shares (in shares) | shares					384,930.724

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