Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

v3.21.1
Document and Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2020
Mar. 19, 2021
Jun. 30, 2020
Document and Entity Information [Abstract]      
Document Type 10-K    
Document Period End Date Dec. 31, 2020    
Entity Registrant Name FATHOM HOLDINGS INC.    
Title of 12(b) Security Common Stock, No Par Value    
Trading Symbol FTHM    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period true    
Entity Shell Company false    
Entity Public Float     $ 178,084,452
Entity Common Stock, Shares Outstanding   13,901,563  
Entity Central Index Key 0001753162    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
Amendment Flag false