Cover Page - USD ($)
 12 Months Ended
Dec. 31, 2021
Mar. 08, 2022
Jun. 30, 2021
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2021    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus FY    
Entity Registrant Name DERMTECH, INC.    
Entity Central Index Key 0001651944    
Entity Well Known Seasoned Issuer No    
Entity Voluntary Filers No    
Current Fiscal Year End Date --12-31    
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    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 978,378,259
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Shell Company false    
Document Annual Report true    
Document Transition Report false    
Entity Common Stock, Shares Outstanding   29,850,730  
Title of 12(b) Security Common Stock, par value $0.0001 per share    
Trading Symbol DMTK    
Security Exchange Name NASDAQ    
ICFR Auditor Attestation Flag true    
Auditor Name KPMG LLP    
Auditor Location San Diego, CA    
Auditor Firm ID 185    
Documents Incorporated by Reference

DOCUMENTS INCORPORATED BY REFERENCE

The registrant intends to file a definitive proxy statement pursuant to Regulation 14A within 120 days after the end of the fiscal year ended December 31, 2021. Portions of such proxy statement are incorporated by reference into Part III of this Form 10‑K.