XML 11 R1.htm IDEA: XBRL DOCUMENT v3.21.1
Document and Entity Information - shares
 3 Months Ended
Mar. 31, 2021
May 17, 2021
Document and Entity Information    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2021  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q1  
Entity Registrant Name CLEARSIGN TECHNOLOGIES CORP  
Entity Central Index Key 0001434524  
Current Fiscal Year End Date --12-31  
Title of 12(b) Security Common Stock  
Trading Symbol CLIR  
Security Exchange Name NASDAQ  
Entity Small Business true  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   31,311,189
Entity Emerging Growth Company false  
Entity Shell Company false