Net Loss per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net loss attributable to Forge Global Holdings, Inc., basic	$ (18,624)	$ (21,188)
Net loss attributable to common stockholders, diluted	$ (18,624)	$ (21,188)
Denominator:
Weighted-average number of shares used to compute net loss per share attributable to common stockholders, basic (in shares)	179,910,522	171,816,522
Weighted-average number of shares used to compute net loss per share attributable to common stockholders, diluted (in shares)	179,910,522	171,816,522
Net loss per share attributable to Forge Global Holdings, Inc. common stockholders:
Basic (in dollars per share)	$ (0.10)	$ (0.12)
Diluted (in dollars per share)	$ (0.10)	$ (0.12)