v3.8.0.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2018
May 04, 2018
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
Trading Symbol RGLS  
Entity Registrant Name REGULUS THERAPEUTICS INC.  
Entity Central Index Key 0001505512  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   104,319,552