| Cover | Oct. 13, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 13, 2021 |
| Entity File Number | 001-38804 |
| Entity Registrant Name | Zynex, Inc. |
| Entity Central Index Key | 0000846475 |
| Entity Tax Identification Number | 90-0275169 |
| Entity Incorporation, State or Country Code | NV |
| Entity Address, Address Line One | 9555 Maroon Circle |
| Entity Address, City or Town | Englewood |
| Entity Address, State or Province | CO |
| Entity Address, Postal Zip Code | 80112 |
| City Area Code | 303 |
| Local Phone Number | 703-4906 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.001 par value per share |
| Trading Symbol | ZYXI |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
