v3.8.0.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2018
Apr. 27, 2018
Entity Registrant Name IRONWOOD PHARMACEUTICALS INC  
Entity Central Index Key 0001446847  
Document Type 10-Q  
Document Period End Date Mar. 31, 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 Q1  
Class A common stock    
Entity Common Stock, Shares Outstanding   137,944,013
Class B common stock    
Entity Common Stock, Shares Outstanding   13,997,357