| Cover | Dec. 19, 2019 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 19, 2019 |
| Entity File Number | 001-35982 |
| Entity Registrant Name | TELARIA, INC. |
| Entity Central Index Key | 0001375796 |
| Entity Tax Identification Number | 20-5480343 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 222 Broadway |
| Entity Address, Address Line Two | 16th Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10038 |
| City Area Code | 646 |
| Local Phone Number | 723-5300 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | TLRA |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
