v3.8.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2017
Oct. 31, 2017
Document and Entity Information [Abstract]    
Entity Registrant Name MANNATECH INC  
Entity Central Index Key 0001056358  
Current Fiscal Year End Date --12-31  
Entity Filer Category Smaller Reporting Company  
Document Type 10-Q  
Document Period End Date Sep. 30, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   2,708,491