Cover Page - shares	3 Months Ended
	Mar. 31, 2020	May 04, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2020
Entity File Number	001-35092
Entity Registrant Name	EXACT SCIENCES CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	02-0478229
Entity Address, Address Line One	441 Charmany Drive
Entity Address, City or Town	Madison
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53719
City Area Code	608
Local Phone Number	535-8815
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	EXAS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001124140
Amendment Flag	false
Entity Common Stock, Shares Outstanding		149,746,169