REVENUE RECOGNITION - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 7,983	$ 11,010	$ 15,291	$ 18,169
Royalty and license
Disaggregation of Revenue [Line Items]
Revenue	7,918	10,881	15,148	17,949
Fixed fee license revenue
Disaggregation of Revenue [Line Items]
Revenue	1,246	1,824	2,991	3,099
Per-unit royalty revenue
Disaggregation of Revenue [Line Items]
Revenue	6,672	9,057	12,157	14,850
Development, services, and other
Disaggregation of Revenue [Line Items]
Revenue	$ 65	$ 129	$ 143	$ 220