Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 30, 2021
Entity Information [Line Items]
Entity Shell Company	false
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Current Reporting Status	Yes
Entity Registrant Name	MANNATECH INC
Entity Central Index Key	0001056358
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		2,063,280