Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Mar. 04, 2022
Jun. 30, 2021
Document and Entity Information [Abstract]        
Document Type 10-K      
Document Annual Report true      
Document Transition Report false      
Document Period End Date Dec. 31, 2021      
Entity File Number 001-39412      
Entity Registrant Name FATHOM HOLDINGS INC.      
Entity Incorporation, State or Country Code NC      
Entity Tax Identification Number 82-1518164      
Entity Address, Address Line One 2000 Regency Parkway Drive      
Entity Address, Address Line Two Suite 300      
Entity Address, City or Town Cary      
Entity Address State Or Province NC      
Entity Address, Postal Zip Code 27518      
City Area Code 888      
Local Phone Number 455-6040      
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 Accelerated Filer      
Entity Small Business true      
Entity Emerging Growth Company true      
Entity Ex Transition Period true      
Entity Shell Company false      
Entity Public Float       $ 169,317,461
Entity Common Stock, Shares Outstanding     17,019,076  
Entity Central Index Key 0001753162      
Current Fiscal Year End Date --12-31      
Document Fiscal Year Focus 2021      
Document Fiscal Period Focus FY      
Amendment Flag false      
ICFR Auditor Attestation Flag false      
Auditor Name Deloitte & Touche LLP BDO USA, LLP    
Auditor Firm ID 34 243    
Auditor Location Raleigh, North Carolina Raleigh, North Carolina