Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands		Total	Series B-1 Convertible Preferred Stock	Series B-2 Convertible Preferred Stock	Previously Reported	Common Stock	Common Stock Previously Reported	Common Stock Revision of Prior Period, Adjustment	Treasury Stock	Additional Paid-In Capital	Additional Paid-In Capital Previously Reported	Accumulated Deficit	Accumulated Deficit Previously Reported	Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income Previously Reported	Noncontrolling Interest	Noncontrolling Interest Previously Reported
Beginning balance (in shares) at Dec. 31, 2020		49,084,185
Beginning balance at Dec. 31, 2020		$ 156,848
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of convertible preferred stock upon conversion of convertible notes and accrued interest (in shares)			27,947
Issuance of convertible preferred stock upon conversion of convertible notes and accrued interest			$ 111
Issuance of convertible preferred stock (in shares)			12,719,398	412,623
Issuance of convertible preferred stock			$ 47,735	$ 1,640
Exchange of Class AA common stock for Series B-1 convertible preferred stock (in shares)		11,669,996
Exchange of Class AA common stock for Series B-1 convertible preferred stock		$ 39,722
Ending balance (in shares) at Dec. 31, 2021		73,914,149			73,914,149
Ending balance at Dec. 31, 2021		$ 246,056			$ 246,056
Beginning balance (in shares) at Dec. 31, 2020						71,119,020
Beginning balance at Dec. 31, 2020		(7,499)				$ 4				$ 52,557		$ (60,060)		$ 0		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unissued common stock (in shares)	[1]							(210,302)
Issuance of Class AA common stock upon exercise of vested stock options, including stock options exercised via promissory notes (in shares)						1,290,307
Issuance of Class AA common stock upon exercise of vested stock options, including stock options exercised via promissory notes		704								704
Issuance of Class AA common stock upon early exercise of unvested stock options (in shares)						2,604,724
Repurchase of early exercised stock options (in shares)						(43,052)
Exchange and settlement of common stock (in shares)						(11,669,996)
Exchange and settlement of common stock		(39,722)								(39,722)
Vesting of early exercised stock options and restricted stock awards		145								145
Share-based compensation expense		12,231								12,231
Net loss		(18,499)										(18,499)
Foreign currency translation adjustment		0
Ending balance (in shares) at Dec. 31, 2021						63,090,701	63,301,003
Ending balance at Dec. 31, 2021		$ (52,640)			$ (52,640)	$ 4	$ 4			25,915	$ 25,915	(78,559)	$ (78,559)	0	$ 0	0	$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of preferred stock to common stock (in shares)		(73,914,149)
Conversion of preferred stock to common stock		$ (246,056)
Ending balance (in shares) at Dec. 31, 2022		0
Ending balance at Dec. 31, 2022		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Pre-close issuance of common stock upon exercise of vested options (in shares)						190,505
Pre-close issuance of common stock upon exercise of vested options		102								102
Pre-close issuance of common stock upon exercise of unvested options (in shares)						4,472
Pre-close issuance common stock for services (in shares)						62,952
Pre-close issuance of common stock for services		621								621
Conversion of preferred stock to common stock (in shares)						73,914,149
Conversion of preferred stock to common stock		246,056				$ 7				246,049
Conversion/Modification of warrants		$ 2,949								2,949
Issuance of Class AA common stock upon exercise of vested stock options, including stock options exercised via promissory notes (in shares)		1,227,310
Repurchase of early exercised stock options (in shares)						(163,054)
Exchange and settlement of common stock		$ 4,207				$ 2				4,205
Issuance of common stock upon Merger (net of redemptions), including PIPE and A&R FPA investors, net of transaction costs (in shares)	[1]					32,171,349
Issuance of common stock upon Merger (net of redemptions), including PIPE and A&R FPA investors, net of transaction costs	[1]	140,811				$ 3				140,808
Issuance of common stock upon exercise of Public Warrants (in shares)						1,994,790
Issuance of common stock upon exercise of Public Warrants		23,638								23,638
Issuance of common stock upon release of restricted stock units (in shares)						139,340
Issuance of common stock upon exercise of vested options (in shares)						954,257
Issuance of common stock upon exercise of vested options		855								854
Issuance of common stock upon early exercise of unvested options (in shares)						78,076
Issuance of common stock upon exercise of Junior Preferred Stock Warrants (in shares)						123,379
Issuance of common stock upon exercise of Junior Preferred Stock Warrants		653								653
Formation of Forge Europe		9,488								3,830						5,658
Vesting of early exercised stock options and restricted stock awards		1,554								1,554
Share-based compensation expense		57,917								57,917
Net loss		(111,905)										(111,859)				(46)
Foreign currency translation adjustment		1,155												693		462
Ending balance (in shares) at Dec. 31, 2022						172,560,916
Ending balance at Dec. 31, 2022		$ 325,461				$ 18				509,094		(190,418)		693		6,074
Treasury Stock, Ending balance (in shares) at Dec. 31, 2022		0							0
Ending balance (in shares) at Dec. 31, 2023		0
Ending balance at Dec. 31, 2023		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class AA common stock upon exercise of vested stock options, including stock options exercised via promissory notes (in shares)		1,268,982
Repurchase of early exercised stock options (in shares)						(202,532)
Issuance of common stock upon exercise of Public Warrants (in shares)		1,994,790
Issuance of common stock upon release of restricted stock units (in shares)						3,788,568
Tax withholding related to vesting of restricted stock units (in shares)						(354,374)
Tax withholding related to vesting of restricted stock units		$ (653)								(653)
Issuance of common stock upon exercise of vested options (in shares)						1,264,429
Issuance of common stock upon exercise of vested options		810								810
Vesting of early exercised stock options and restricted stock awards		262								262
Share-based compensation expense		34,334								34,334
Common stock repurchases (in shares)						(157,193)
Common stock repurchases		(625)							$ (625)
Net loss		(91,549)										(90,221)				(1,328)
Foreign currency translation adjustment		378												218		160
Ending balance (in shares) at Dec. 31, 2023						176,899,814
Ending balance at Dec. 31, 2023		$ 268,418				$ 18				$ 543,847		$ (280,639)		$ 911		$ 4,906
Treasury Stock, Ending balance (in shares) at Dec. 31, 2023		(157,193)							(625,000)

[1] This amount represents shares that were not issued upon the closing of the Business Combination as a result of a stockholder’s demand for appraisal rights. See Note 3, "Recapitalization" for additional information. These shares were issued to the stockholder during the year ended December 31, 2022 after the statutory period to perfect such rights lapsed.