Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

v3.6.0.2
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2016
Mar. 01, 2017
Jun. 30, 2016
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2016    
Document Fiscal Year Focus 2016    
Document Fiscal Period Focus FY    
Trading Symbol CBAY    
Entity Registrant Name CYMABAY THERAPEUTICS, INC.    
Entity Central Index Key 0001042074    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Smaller Reporting Company    
Entity Common Stock, Shares Outstanding   28,752,451  
Entity Public Float     $ 37,357,482