Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Feb. 28, 2019
Jun. 29, 2018
Document And Entity Information [Abstract]      
Entity Registrant Name SYROS PHARMACEUTICALS, INC.    
Trading Symbol SYRS    
Entity Central Index Key 0001556263    
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 Accelerated Filer    
Entity Common Stock, Shares Outstanding   32,766,624  
Entity Public Float     $ 258,458,840
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Entity Small Business true    
Entity Ex Transition Period true    
Entity Emerging Growth Company true    
Entity Shell Company false