v3.19.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
May 03, 2019
Document and Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Entity Registrant Name ENZON PHARMACEUTICALS, INC.  
Entity Central Index Key 0000727510  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Trading Symbol ENZN  
Entity Common Stock, Shares Outstanding   44,214,603
Entity Emerging Growth Company false  
Entity Small Business true