| Cover | Jan. 25, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jan. 25, 2021 |
| Current Fiscal Year End Date | --12-31 |
| Entity File Number | 001-08568 |
| Entity Registrant Name | TELIGENT, INC. |
| Entity Central Index Key | 0000352998 |
| Entity Tax Identification Number | 01-0355758 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 105 Lincoln Avenue |
| Entity Address, City or Town | Buena |
| Entity Address, State or Province | NJ |
| Entity Address, Postal Zip Code | 08310 |
| City Area Code | 856 |
| Local Phone Number | 697-1441 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | TLGT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
