Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 28, 2021	Jun. 30, 2020
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	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding (shares)		2,069,259
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Public Float			$ 33,457,599
Document Transition Report	false
City Area Code	75028
Entity File Number	000-24657
Local Phone Number	471-7400
Entity Tax Identification Number	75-2508900
Trading Symbol	MTEX
City Area Code	972
Entity Incorporation, State or Country Code	TX
Entity Address, Address Line One	1410 Lakeside Parkway, Suite 200,
Entity Address, State or Province	TX
Entity Address, City or Town	Flower Mound,