FAIR VALUE - Schedule of Fair Value Hierarchy for Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Liabilities:
Short-term contingent consideration	$ 6,776	$ 0
Long-term contingent consideration	31,776	168
Recurring
Assets:
Total	77	9,629
Liabilities:
Short-term contingent consideration	6,776
Long-term contingent consideration	31,776
Contingent consideration liability		168
Total	38,552	168
Recurring | Level 1
Assets:
Total	77	0
Liabilities:
Short-term contingent consideration	0
Long-term contingent consideration	0
Contingent consideration liability		0
Total	0	0
Recurring | Level 2
Assets:
Total	0	9,629
Liabilities:
Short-term contingent consideration	0
Long-term contingent consideration	0
Contingent consideration liability		0
Total	0	0
Recurring | Level 3
Assets:
Total	0	0
Liabilities:
Short-term contingent consideration	6,776
Long-term contingent consideration	31,776
Contingent consideration liability		168
Total	38,552	$ 168
Recurring | Money market funds
Assets:
Cash and cash equivalents	77
Recurring | Money market funds | Level 1
Assets:
Cash and cash equivalents	77
Recurring | Money market funds | Level 2
Assets:
Cash and cash equivalents	0
Recurring | Money market funds | Level 3
Assets:
Cash and cash equivalents	0
Recurring | Collegium warrants
Assets:
Investments	9,629
Recurring | Collegium warrants | Level 1
Assets:
Investments	0
Recurring | Collegium warrants | Level 2
Assets:
Investments	9,629
Recurring | Collegium warrants | Level 3
Assets:
Investments	$ 0