| Cover | Aug. 11, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 11, 2022 |
| Entity Registrant Name | Forge Global Holdings, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39794 |
| Entity Tax Identification Number | 98-1561111 |
| Entity Address, Address Line One | 415 Mission St. |
| Entity Address, Address Line Two | Suite 5510 |
| Entity Address, City or Town | San Francisco, |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94105 |
| City Area Code | (415) |
| Local Phone Number | 881-1612 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.0001 par value per share |
| Trading Symbol | FRGE |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001827821 |
| Amendment Flag | false |
