Cover - shares
6 Months Ended
Jun. 30, 2020
Aug. 10, 2020
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2020  
Document Transition Report false  
Entity File Number 001-33843  
Entity Registrant Name Synacor, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 16-1542712  
Entity Address, Address Line One 40 La Riviere Drive, Suite 300  
Entity Address, City or Town Buffalo,  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 14202  
City Area Code 716  
Local Phone Number 853-1362  
Title of 12(b) Security Common Stock, $0.01 Par Value  
Trading Symbol SYNC  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   39,459,391
Amendment Flag false  
Document Fiscal Year Focus 2020  
Document Fiscal Period Focus Q2  
Entity Central Index Key 0001408278  
Current Fiscal Year End Date --12-31