v3.10.0.1
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2018
Jul. 31, 2018
Entity Registrant Name IRONWOOD PHARMACEUTICALS INC  
Entity Central Index Key 0001446847  
Document Type 10-Q  
Document Period End Date Jun. 30, 2018  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q2  
Class A common stock    
Entity Common Stock, Shares Outstanding   139,180,559
Class B common stock    
Entity Common Stock, Shares Outstanding   13,976,855