Equity - Warrants - Narrative (Details)	9 Months Ended
Sep. 30, 2026 shares
Equity [Abstract]
Warrants issued (in shares)	0
Warrants exercised (in shares)	0
Warrants cancelled (in shares)	0

Class of Warrant Or Right, Outstanding, Warrants Cancelled

No definition available.

Name:	rnac_ClassOfWarrantOrRightOutstandingWarrantsCancelled
Namespace Prefix:	rnac_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration