Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 27, 2021
Document and Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Sep. 30, 2021
Document Quarterly Report	true
Document Transition Report	false
Entity Registrant Name	ZYNEX INC
Entity Current Reporting Status	Yes
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, $0.001 par value per share
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		34,779,691
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000846475
Amendment Flag	false
Trading Symbol	ZYXI
Entity File Number	001-38804
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	90-0275169
Entity Address, Address Line One	9655 Maroon Cir.
Entity Address, City or Town	Englewood
Entity Address, Country	CO
Entity Address, Postal Zip Code	80112
City Area Code	303
Local Phone Number	703-4906