Consolidated Statement of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss		$ (91,549)	$ (111,905)	$ (18,499)
Adjustments to reconcile net loss to net cash (used in) provided by operations:
Share-based compensation		34,334	57,924	12,231
Depreciation and amortization		6,954	6,026	5,390
Amortization of right-of-use assets		3,153	3,999	2,804
Loss on impairment of long lived assets		599	446	0
Bad debt reserve		270	433	121
Change in fair value of warrant liabilities		6,465	(19,836)	6,064
Change in fair value of contingent liability	[1]	2,545	0	0
Settlement of related party promissory notes		0	5,517	0
Other		(625)	3,132	107
Changes in operating assets and liabilities:
Accounts receivable		(792)	1,403	382
Prepaid expenses and other assets		2,018	(3,321)	(1,031)
Accounts payable		(1,216)	904	(692)
Accrued expenses and other liabilities		2,805	(788)	(520)
Accrued compensation and benefits		(2,267)	(7,911)	8,080
Operating lease liabilities		(4,150)	(4,829)	(3,536)
Net cash (used in) provided by operating activities		(41,456)	(68,806)	10,901
Cash flows from investing activities:
Receipts of term deposit maturities		2,115	0	0
Purchases of property and equipment		(527)	(220)	0
Purchases of term deposit		(9,748)	0	0
Purchases of intangible assets		0	(118)	(2,202)
Capitalized internal-use software development costs		0	(6,312)	(1,054)
Net cash used in investing activities		(8,160)	(6,650)	(3,256)
Cash flows from financing activities:
Proceeds from exercise of options, including proceeds from repayment of promissory notes		710	1,086	1,621
Taxes withheld and paid related to net share settlement of equity awards		(653)	0	0
Proceeds from PIPE investment and A&R FPA investors		0	208,500	0
Proceeds from exercise of Public Warrants		0	22,940	0
Formation of Forge Europe		0	9,488	0
Proceeds from the Merger		0	7,865	0
Payments for redemption of Public Warrants		0	(165)	0
Payments for offering costs		0	(56,852)	(4,954)
Cash paid to purchase equity awards		0	0	(23)
Repayment of notes payable		0	0	(19,438)
Net cash provided by financing activities		57	192,862	26,581
Effect of changes in currency exchange rates on cash and cash equivalents		378	1,155	0
Net (decrease) increase in cash and cash equivalents		(49,181)	118,561	34,226
Cash, cash equivalents and restricted cash, beginning of the period		194,965	76,404	42,178
Cash, cash equivalents and restricted cash, end of the period		145,784	194,965	76,404
Reconciliation of cash, cash equivalents and restricted cash to the amounts reported within the consolidated balance sheets
Cash and cash equivalents		144,722	193,136	74,781
Restricted cash		1,062	1,829	1,623
Total cash, cash equivalents and restricted cash, end of the period		145,784	194,965	76,404
Supplemental disclosures of cash flow information:
Cash paid for interest		0	0	2,118
Supplemental disclosure of non-cash investing and financing activities:
Lease liabilities arising from obtaining right-of-use assets		1,755	3,087	1,702
Vesting of early exercised stock options and restricted stock awards		262	1,554	145
Purchase of property and equipment accrued and not yet paid		250	0	0
Conversion of preferred stock		0	246,049	0
Assumption of merger warrants liability		0	13,983	0
Reclassification of deferred offering costs to equity		0	5,923	0
Issuance of common stock upon settlement of related party promissory notes		0	4,207	0
Warrants issued in connection with A&R FPA		0	3,080	0
Conversion of May 2020 and October 2020 preferred stock warrants of Legacy Forge to common stock warrants		0	2,949	0
Early exercise of stock options upon settlement of related party promissory notes		0	1,310	0
Warrant liability reclassified to additional paid-in capital upon exercise of Public Warrants		0	698	0
Warrant liability reclassified to additional paid-in capital upon exercise of Junior Preferred Stock Warrants		0	653	0
Non-cash assets acquired in the Merger		0	193	0
Capitalized internal-use software development costs accrued and not yet paid		0	180	214
Exchange of Class AA common stock for Series B-1 convertible preferred stock		0	0	39,722
Deferred offering cost accrued and not yet paid		0	0	969
Series B-1 Convertible Preferred Stock
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock, net of issuance costs		0	0	47,735
Supplemental disclosure of non-cash investing and financing activities:
Conversion of convertible notes into Series B-1 convertible preferred stock		0	0	111
Series B-2 Convertible Preferred Stock
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock, net of issuance costs		$ 0	$ 0	$ 1,640

[1] The change in fair value of contingent liability in connection with the modification of Junior Preferred warrants ( December 2023 Warrants) is recorded in the consolidated statement of operations within General and administrative expense. See Note 4, "Fair Value Measurements," for additional information.