Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

v3.19.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Mar. 07, 2019
Jun. 30, 2018
Document And Entity Information [Abstract]      
Entity Registrant Name FINJAN HOLDINGS, INC.    
Trading Symbol FNJN    
Entity Central Index Key 0001366340    
Current Fiscal Year End Date --12-31    
Entity Filer Category Non-accelerated Filer    
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Emerging Growth Company false    
Entity Small Business true    
Entity Common Stock, Shares Outstanding   27,595,840  
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 71,238,731
Entity Shell Company false