| Cover Page | Oct. 19, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 22, 2020 |
| Entity Registrant Name | LIMELIGHT NETWORKS, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-33508 |
| Entity Tax Identification Number | 20-1677033 |
| Entity Address, Address Line One | 1465 North Scottsdale Road |
| Entity Address, Address Line Two | Suite 400 |
| Entity Address, City or Town | Scottsdale |
| Entity Address, State or Province | AZ |
| Entity Address, Postal Zip Code | 85257 |
| City Area Code | 602 |
| Local Phone Number | 850-5000 |
| Title of 12(b) Security | Common stock, par value $0.001 per share |
| Trading Symbol | LLNW |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001391127 |
| Amendment Flag | false |
