Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
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		5,315,739
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	41-1519168
City Area Code	(651)
Local Phone Number	603-7700
Entity Incorporation, State or Country Code	MN
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Common Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	ISNS
Security Exchange Name	NASDAQ
Rights [Member]
Entity Information [Line Items]
Title of 12(b) Security	Preferred Stock Purchase Rights
Trading Symbol	ISNS
Security Exchange Name	NASDAQ