Common Stock and Noncontrolling Interest in Subsidiaries - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended						12 Months Ended
	Nov. 30, 2022	Oct. 31, 2022	Jul. 31, 2022	Mar. 31, 2022	Jul. 31, 2021	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Jun. 30, 2022
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Common stock, shares authorized							150,000,000	150,000,000
Common stock, voting rights								Each share of common stock entitles the holder to one vote and to receive dividends when and if declared by the board of directors of the Company.
Shares issued							0	0
Shares sold/issued							45,796,449	44,292,102
Losses attributed to noncontrolling interests							$ (2,019)	$ (1,915)
Net issuance of common stock under equity-based compensation plans							6,020	3,281
Purchase of shares				6,700,000		700,000
Equity-based compensation expense							$ 27,957	$ 24,375
Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued during period								13,685,000
Cullinan Mica | Stock Purchase And Transfer Agreements
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Stock issued during period shares purchase of assets	900,000
Cullinan Mica | HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Stock options held by noncontrolling interests							200,000
Cullinan Mica | Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Stock issued during period shares purchase of assets	900,000
Stock Issued During Period, Value, Purchase of Assets	$ 2,600
Cullinan Mica | Common Stock | Stock Purchase And Transfer Agreements
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Stock issued during period shares purchase of assets	400,000
Maximum | Noncontrolling Interests in Subsidiaries | HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests							$ 400	$ 100
Series A Preferred Stock | Cullinan Mica | Stock Purchase And Transfer Agreements
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Stock issued during period shares purchase of assets		1,500,000
Series A-2 Junior Preferred Stock | Cullinan Mica | Stock Purchase And Transfer Agreements
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Stock issued during period shares purchase of assets		11,500,000
Series A Junior Preferred Stock | Cullinan Mica | Stock Purchase And Transfer Agreements
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Stock issued during period shares purchase of assets		2,000,000.0
Cullinan Amber Corp | MIT License Agreement between Amber and MIT | Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued	500,000								300,000
Shares sold/issued						200,000
Cullinan Amber Corp | Dr. Wittrup | Common Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued	200,000
Cullinan Amber Corp | Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued	10,000,000.0					3,000,000.0			6,000,000.0
Ownership interest percentage							6.00%
Percentage of share purchased as part of asset acquisition							94.00%
Cullinan Florentine Corp | HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests							$ 0
Cullinan Florentine Corp | Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Ownership interest percentage							4.00%
Percentage of share purchased as part of asset acquisition							96.00%
Cullinan Florentine Corp | Series B Preferred Units
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares issued during period			3,750,000		7,500,000
Cullinan Pearl Corp | HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests							$ 300	700
MICA
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Losses attributed to noncontrolling interests							$ 1,200	$ 1,100
Ownership interest percentage							5.00%
Percentage of share purchased as part of asset acquisition							95.00%
MICA | HLBV
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Shares price per share							$ 0.22
Share-based payment award, accelerated vesting, number		300,000
Equity-based compensation expense		$ 600
MICA | Series A Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Ownership interest percentage							4.00%
Percentage of share purchased as part of asset acquisition							96.00%
MICA | Series A Senior Preferred Stock
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Purchase of shares						5,400,000
MICA | Series A Senior Preferred Stock | Investor
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds				$ 1,200		$ 900
Purchase of shares				900,000
MICA | Series A-2 Junior Preferred Stock | Cullinan Mica | Stock Purchase And Transfer Agreements
Common Stock And Noncontrolling Interest In Subsidiaries [Line Items]
Gross proceeds		$ 30,700