INTANGIBLE ASSETS - Amortization (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 5,952	$ 5,174
Research and development
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	286	289
Selling, general and administrative
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 5,666	$ 4,885