REVENUE - Royalties and Milestone Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues	$ 25,472	$ 34,565	$ 77,686	$ 76,099
Royalties and milestone - CAMBIA Canada
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues	$ 400	$ 300	$ 1,400	$ 1,200