Stockholders' Equity - Schedule of development subsidiaries and their product candidates (Details) - Subsidiaries [Member]	Dec. 31, 2023
Cullinan Amber Corp [Member]
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Subsidiary, Ownership Percentage	94.00%
Cullinan Florentine Corp [Member]
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Subsidiary, Ownership Percentage	96.00%
Cullinan M I C A Corp [Member]
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Subsidiary, Ownership Percentage	95.00%