Document and Entity Information - shares
9 Months Ended
Sep. 30, 2019
Nov. 04, 2019
Cover [Abstract]    
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 EyePoint Pharmaceuticals, Inc.  
Entity Central Index Key 0001314102  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Trading Symbol EYPT  
Entity Common Stock, Shares Outstanding   108,117,440
Entity Emerging Growth Company false  
Entity Small Business true  
Entity Shell Company false  
Entity File Number 000-51122  
Entity Tax Identification Number 26-2774444  
Entity Address, Address Line One 480 Pleasant Street  
Entity Address, City or Town Watertown  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 02472  
City Area Code (617)  
Local Phone Number 926-5000  
Document Quarterly Report true  
Document Transition Report false  
Entity Incorporation, State or Country Code DE  
Title of 12(b) Security Common Stock, par value $0.001  
Security Exchange Name NASDAQ  
Entity Interactive Data Current Yes  
Entity Current Reporting Status Yes