Derivatives - Schedule of Liabilities Measured and Recognized at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	May 28, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability			$ 5,600	$ 6,300
Fair Value, Recurring
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	$ 0	$ 7,507
Fair Value, Recurring \| Convertible Notes Payable \| 2023 Series D Convertible Notes
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	0	7,507
Fair Value, Recurring \| (Level 1)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	0	0
Fair Value, Recurring \| (Level 1) \| Convertible Notes Payable \| 2023 Series D Convertible Notes
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	0	0
Fair Value, Recurring \| (Level 2)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	0	0
Fair Value, Recurring \| (Level 2) \| Convertible Notes Payable \| 2023 Series D Convertible Notes
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	0	0
Fair Value, Recurring \| (Level 3)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	0	7,507
Fair Value, Recurring \| (Level 3) \| Convertible Notes Payable \| 2023 Series D Convertible Notes
Derivative Instruments, Gain (Loss) [Line Items]
Derivative liability	$ 0	$ 7,507

Teligent, Inc. 10-Q