Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Palantir	PIPE Investors	Series A Redeemable Convertible Preferred Stock	Series B Redeemable Convertible Preferred Stock	Series X Redeemable Convertible Preferred Stock	Common Stock	Common Stock Palantir	Common Stock PIPE Investors	Treasury Stock	Additional Paid-in Capital	Additional Paid-in Capital Palantir	Additional Paid-in Capital PIPE Investors	Accumulated Deficit
Balance at Dec. 31, 2019	$ (327,420)						$ 1				$ 27,909			$ (355,330)
Temporary Equity, Balance (in Shares) at Dec. 31, 2019				29,484,740	27,552,236	11,953,274
Temporary Equity, Balance at Dec. 31, 2019				$ 184,247	$ 206,035	$ 75,000
Balance (in Shares) at Dec. 31, 2019							18,421,084			(13,975)
Exercise of stock options	15										15
Exercise of stock options (in Shares)							3,843
Stock-based compensation expense	828										828
Share issuance costs					(15)
Issuance of Series B redeemable convertible preferred stock					$ 84,596
Issuance of Series B redeemable convertible preferred stock (in Shares)					13,620,063
Net income loss	(30,200)													(30,200)
Balance at Mar. 31, 2020	(356,777)						$ 1				28,752			(385,530)
Temporary Equity, Balance (in Shares) at Mar. 31, 2020				29,484,740	41,172,299	11,953,274
Temporary Equity, Balance at Mar. 31, 2020				$ 184,247	$ 290,616	$ 75,000
Balance (in Shares) at Mar. 31, 2020							18,424,927			(13,975)
Stock-based compensation expense	1,444										1,444
Net income loss	(135,618)													(135,618)
Balance at Jun. 30, 2020	(490,951)						$ 1				30,196			(521,148)
Temporary Equity, Balance (in Shares) at Jun. 30, 2020				29,484,740	41,172,299	11,953,274
Temporary Equity, Balance at Jun. 30, 2020				$ 184,247	$ 290,616	$ 75,000
Balance (in Shares) at Jun. 30, 2020							18,424,927			(13,975)
Exercise of stock options	37										37
Exercise of stock options (in Shares)							81,838
Repurchase of common stock	(256)									$ (256)
Repurchase of common stock (in Shares)										(76,859)
Stock-based compensation expense	1,083										1,083
Net income loss	(46,325)													(46,325)
Balance at Sep. 30, 2020	(536,412)						$ 1			$ (256)	31,316			(567,473)
Temporary Equity, Balance (in Shares) at Sep. 30, 2020				29,484,740	41,172,299	11,953,274
Temporary Equity, Balance at Sep. 30, 2020				$ 184,247	$ 290,616	$ 75,000
Balance (in Shares) at Sep. 30, 2020							18,506,765			(90,834)
Balance at Dec. 31, 2020	(531,400)						$ 1			$ (256)	32,418			(563,563)
Temporary Equity, Balance (in Shares) at Dec. 31, 2020				29,484,740	41,205,482	11,953,274
Temporary Equity, Balance at Dec. 31, 2020				$ 184,247	$ 290,866	$ 75,000
Balance (in Shares) at Dec. 31, 2020							18,529,453			(90,834)
Stock-based compensation expense	1,009										1,009
Net income loss	(81,539)													(81,539)
Balance at Mar. 31, 2021	(611,930)						$ 1			$ (256)	33,427			(645,102)
Temporary Equity, Balance (in Shares) at Mar. 31, 2021				29,484,740	41,205,482	11,953,274
Temporary Equity, Balance at Mar. 31, 2021				$ 184,247	$ 290,866	$ 75,000
Balance (in Shares) at Mar. 31, 2021							18,529,453			(90,834)
Balance at Dec. 31, 2020	(531,400)						$ 1			$ (256)	32,418			(563,563)
Temporary Equity, Balance (in Shares) at Dec. 31, 2020				29,484,740	41,205,482	11,953,274
Temporary Equity, Balance at Dec. 31, 2020				$ 184,247	$ 290,866	$ 75,000
Balance (in Shares) at Dec. 31, 2020							18,529,453			(90,834)
Balance at Sep. 30, 2021	96,216						$ 10				755,847			(659,641)
Temporary Equity, Balance (in Shares) at Sep. 30, 2021				0	0	0
Balance (in Shares) at Sep. 30, 2021							123,464,113
Balance at Mar. 31, 2021	(611,930)						$ 1			$ (256)	33,427			(645,102)
Temporary Equity, Balance (in Shares) at Mar. 31, 2021				29,484,740	41,205,482	11,953,274
Temporary Equity, Balance at Mar. 31, 2021				$ 184,247	$ 290,866	$ 75,000
Balance (in Shares) at Mar. 31, 2021							18,529,453			(90,834)
Exercise of stock options	14										14
Exercise of stock options (in Shares)							3,711
Stock-based compensation expense	28,188										28,188
Net income loss	(64,477)													(64,477)
Balance at Jun. 30, 2021	(648,205)						$ 1			$ (256)	61,629			(709,579)
Temporary Equity, Balance (in Shares) at Jun. 30, 2021				29,484,740	41,205,482	11,953,274
Temporary Equity, Balance at Jun. 30, 2021				$ 184,247	$ 290,866	$ 75,000
Balance (in Shares) at Jun. 30, 2021							18,533,164			(90,834)
Recapitalization from GX Acquisition Corp. merger, net of redemptions and equity issuance and merger costs	485,596						$ 8			$ 256	485,332
Recapitalization net of redemptions and equity issuance and merger costs redeemable convertible preferred stock (in Shares)				(29,484,740)	(41,205,482)	(11,953,274)
Recapitalization net of redemptions and equity issuance and merger costs redeemable convertible preferred stock				$ (184,247)	$ (290,866)	$ (75,000)
Recapitalization from GX Acquisition Corp. merger, net of redemptions and equity issuance and merger costs (in Shares)							94,122,404			90,834
Equity classification of Legacy Celularity warrants	96,398										96,398
Issuance of common stock		$ 20,000	$ 83,400						$ 1			$ 20,000	$ 83,399
Issuance of common stock (in Shares)								2,000,000	8,340,000
Exercise of stock options	209										209
Exercise of stock options (in Shares)							468,545
Stock-based compensation expense	8,880										8,880
Net income loss	49,938													49,938
Balance at Sep. 30, 2021	$ 96,216						$ 10				$ 755,847			$ (659,641)
Temporary Equity, Balance (in Shares) at Sep. 30, 2021				0	0	0
Balance (in Shares) at Sep. 30, 2021							123,464,113