XML 58 R1.htm IDEA: XBRL DOCUMENT v3.22.1
Document and Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Mar. 29, 2022
Jun. 30, 2021
Document and Entity Information        
Document Type 10-K      
Document Annual Report true      
Document Period End Date Dec. 31, 2021      
Document Transition Report false      
Entity Registrant Name CLEARSIGN TECHNOLOGIES CORP      
Entity File Number 001-35521      
Entity Incorporation, State or Country Code WA      
Entity Tax Identification Number 26-2056298      
Entity Address, Address Line One 8023 East 63rd Place, Suite 101      
Entity Address, City or Town Tulsa      
Entity Address, State or Province OK      
Entity Address, Postal Zip Code 74133      
City Area Code 206      
Local Phone Number 673-4848      
Title of 12(b) Security Common Stock      
Trading Symbol CLIR      
Security Exchange Name NASDAQ      
Entity Current Reporting Status Yes      
Entity Interactive Data Current Yes      
Entity Filer Category Non-accelerated Filer      
Entity Small Business true      
Entity Emerging Growth Company false      
ICFR Auditor Attestation Flag false      
Entity Well-known Seasoned Issuer No      
Entity Voluntary Filers No      
Entity Public Float       $ 120,917,861
Entity Shell Company false      
Entity Common Stock, Shares Outstanding     32,150,996  
Entity Central Index Key 0001434524      
Document Fiscal Year Focus 2021      
Current Fiscal Year End Date --12-31      
Document Fiscal Period Focus FY      
Amendment Flag false      
Auditor Name BPM LLP Gumbiner Savett Inc.    
Auditor Location Santa Monica, California Santa Monica, California    
Auditor Firm ID 207 285