Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Registrant Name	IMAGE SENSING SYSTEMS INC
Entity Central Index Key	0000943034
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		5,309,259
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	0-26056
Entity Address, Address Line One	500 Spruce Tree Centre
Entity Address, Address Line Two	1600 University Avenue West
Entity Address, City or Town	St. Paul
Entity Address, State or Province	MN
Entity Address, Postal Zip Code	55104
Entity Tax Identification Number	411519168
City Area Code	(651)
Local Phone Number	603-7700