SEGMENTS - Geographical Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Revenues	$ 58,853	$ 28,222	$ 112,083	$ 73,731
Property and equipment	13,095		13,095		$ 13,865
United States
Segment Reporting Information [Line Items]
Revenues	54,145	26,750	103,262	66,778
Property and equipment	8,886		8,886		9,549
United Kingdom
Segment Reporting Information [Line Items]
Revenues	4,708	$ 1,472	8,821	$ 6,953
Property and equipment	4,096		4,096		4,162
INDIA [Domain]
Segment Reporting Information [Line Items]
Property and equipment	$ 113		$ 113		$ 154