Document and Entity Information - shares
3 Months Ended
Mar. 31, 2017
May 04, 2017
Document and Entity Information    
Entity Registrant Name GENOCEA BIOSCIENCES, INC.  
Entity Central Index Key 0001457612  
Document Type 10-Q  
Document Period End Date Mar. 31, 2017  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding (in shares)   28,504,775
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q1