Convertible Preferred Stock - Voting (Narrative) (Details)	Dec. 31, 2025
Equity [Abstract]
Preferred stock, convertible, transaction restrictions, percentage of originally issued stock issued and outstanding	30.00%

Preferred Stock, Convertible, Transaction Restrictions, Percentage Of Originally Issued Stock Issued And Outstanding

No definition available.

Name:	rnac_PreferredStockConvertibleTransactionRestrictionsPercentageOfOriginallyIssuedStockIssuedAndOutstanding
Namespace Prefix:	rnac_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant