v3.19.1
Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Feb. 28, 2019
Jul. 18, 2018
Document and Entity Information      
Entity Registrant Name Rubius Therapeutics, Inc.    
Entity Central Index Key 0001709401    
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Non-accelerated Filer    
Entity Public Float     $ 718.9
Entity Small Business false    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding   79,529,965  
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY