SEGMENT AND GEOGRAPHICAL INFORMATION - Summary of Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenues:
Revenues	$ 43,635	$ 1,789	$ 58,380	$ 117,094
Property and equipment, net:
Property and equipment, net	13,909		13,909		$ 17,056
U.S. [Member]
Revenues:
Revenues	5,070	1,185	12,446	9,312
Property and equipment, net:
Property and equipment, net	6,173		6,173		7,145
Not connected to a country [Member]
Revenues:
Revenues	34,830	136	36,397	101,910
Property and equipment, net:
Property and equipment, net	5,423		5,423		6,242
Other [Member]
Revenues:
Revenues	3,735	$ 468	9,537	$ 5,872
Property and equipment, net:
Property and equipment, net	$ 2,313		$ 2,313		$ 3,669