Cover Page - shares	3 Months Ended
	Mar. 31, 2021	May 21, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-08568
Entity Registrant Name	Teligent, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	01-0355758
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
Title of 12(b) Security	Common Stock, Par Value $0.01 Per Share
Trading Symbol	TLGT
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		92,817,493
Entity Central Index Key	0000352998
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2021
Amendment Flag	false
Current Fiscal Year End Date	--12-31