Annual report pursuant to Section 13 and 15(d)

Document And Entity Information

v3.8.0.1
Document And Entity Information - USD ($)
12 Months Ended
Dec. 31, 2017
Mar. 01, 2018
Jun. 30, 2017
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2017    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2017    
Entity Registrant Name COMMUNICATIONS SYSTEMS INC    
Entity Central Index Key 0000022701    
Current Fiscal Year End Date --12-31    
Entity Filer Category Smaller Reporting Company    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Well-known Seasoned Issuer No    
Entity Public Float     $ 30,627,000
Entity Common Stock, Shares Outstanding   8,982,169