Unaudited Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Cash flows from operating activities:
Net loss attributable to Forge Global Holdings, Inc.	$ (16,198)	$ (64,424)	$ (5,074)	$ 938	$ (85,741)	$ (12,139)
Adjustments to reconcile net loss including noncontrolling interest to net cash (used in) provided by operations:
Share-based compensation					45,974	9,975
Depreciation and amortization					4,531	4,137
Transaction expenses related to the Merger					3,132	0
Amortization of right-of-use assets					2,819	1,992
Loss on impairment of long lived assets					446	0
Bad debt reserve					294	0
Change in fair value of warrant liabilities	(25,210)		(737)		(19,808)	5,575
Gain (Loss) on Extinguishment of Debt					5,517	0
Other					0	285
Changes in operating assets and liabilities:
Accounts receivable					2,042	1,560
Prepaid expenses and other assets					(4,265)	469
Accounts payable					(43)	333
Accrued expenses and other liabilities					402	(2,092)
Accrued compensation and benefits					(11,118)	5,388
Operating lease liabilities					(3,942)	(2,626)
Net cash (used in) provided by operating activities					(59,760)	12,857
Cash flows from investing activities:
Purchases of property and equipment					(116)	0
Purchases of intangible assets					(126)	(2,202)	$ (2,200)
Capitalized internal-use software development costs					(4,590)	(653)
Net cash used in investing activities					(4,832)	(2,855)
Cash flows from financing activities:
Proceeds from the Merger					7,865	0
Proceeds from PIPE investment and A&R FPA investors					208,500	0
Payments for offering costs					(56,852)	(1,750)
Proceeds from exercise of Public Warrants					22,940	0
Formation of Forge Europe (Note 1)					9,488	0
Proceeds from exercise of options, including proceeds from repayment of promissory notes					997	1,460
Payments for redemption of Public Warrants					(165)	0
Repayment of notes payable					0	(19,437)
Payments to repurchase early exercised stock options					0	(10)
Net cash provided by financing activities					192,773	29,638
Effect of changes in currency exchange rates on cash and cash equivalents					(159)	0
Net increase in cash and cash equivalents					128,022	39,640
Cash, cash equivalents and restricted cash, beginning of the period		$ 76,404		$ 42,178	76,404	42,178	42,178
Cash, cash equivalents and restricted cash, end of the period	204,426		81,818		204,426	81,818	76,404
Reconciliation of cash, cash equivalents and restricted cash to the amounts reported within the unaudited condensed consolidated balance sheets
Cash and cash equivalents	202,603		80,450		202,603	80,450	74,781
Restricted cash	1,823		1,368		1,823	1,368	1,623
Total cash, cash equivalents and restricted cash, end of the period	$ 204,426		$ 81,818		204,426	81,818	$ 76,404
Supplemental disclosures of cash flow information:
Cash paid for interest					0	2,118
Supplemental disclosure of non-cash investing and financing activities:
Capitalized internal-use software development costs accrued and not yet paid					234	97
Reclassification of deferred offering costs to equity					5,932	0
Conversion of preferred stock					246,049	0
Conversion of May 2020 and October 2020 preferred stock warrants of Legacy Forge to common stock warrants					2,949	0
Non-cash assets acquired in the Merger					193	0
Warrants issued in connection with A&R FPA					3,080	0
Conversion of May 2020 and October 2020 preferred stock warrants of Legacy Forge to common stock warrants					13,983	0
Recapitalization of Legacy Forge common stock					5	0
Exchange of Class AA common stock for Series B-1 convertible preferred stock					0	39,722
Vesting of early exercised stock options and restricted stock awards					1,240	102
Warrant liability reclassified to additional paid-in capital upon exercise of Public Warrants					698	0
Warrant liability reclassified to additional paid-in capital upon exercise of Junior Preferred Stock Warrants					653	0
Settlement of promissory notes					4,207	0
Early exercise of stock options upon settlement of related party promissory notes					1,310	0
Series B-1
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock, net of issuance costs					0	47,735
Series B-2
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock, net of issuance costs					$ 0	$ 1,640