Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 28, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Title of 12(b) Security	Common Stock, $.001 par value
Trading Symbol	ATRC
Security Exchange Name	NASDAQ
Entity Registrant Name	AtriCure, Inc.
Entity Central Index Key	0001323885
Current Fiscal Year End Date	--12-31
Entity File Number	000-51470
Entity Address, Address Line One	7555 Innovation Way
Entity Address, City or Town	Mason
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	45040
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	34-1940305
City Area Code	513
Local Phone Number	755-4100
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		39,550,453