INTANGIBLE ASSETS - Intangible Assets Amortization Expense for Long-lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization expense	$ 381	$ 388
Cost of revenue
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization expense	146	146
Sales and marketing
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization expense	$ 235	235
Research and development
Finite-Lived Intangible Assets [Line Items]
Total intangible amortization expense		$ 7