Document and Entity Information
3 Months Ended
Jun. 30, 2014
Jul. 28, 2014
Document and Entity Information    
Entity Registrant Name Celldex Therapeutics, Inc.  
Entity Central Index Key 0000744218  
Document Type 10-Q  
Document Period End Date Jun. 30, 2014  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   89,403,761
Document Fiscal Year Focus 2014  
Document Fiscal Period Focus Q2