| Document and Entity Information | Nov. 09, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 9, 2021 |
| Entity Registrant Name | DERMTECH, INC. |
| Entity Central Index Key | 0001651944 |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity File Number | 001-38118 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 84-2870849 |
| Entity Address, Address Line One | 11099 N. Torrey Pines Road |
| Entity Address, Address Line Two | Suite 100 |
| Entity Address, City or Town | La Jolla |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92037 |
| City Area Code | 858 |
| Local Phone Number | 450-4222 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock,par value $0.0001 per share |
| Trading Symbol | DMTK |
| Security Exchange Name | NASDAQ |
