INCOME TAXES - Income Tax Reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory U.S. federal tax rate	21.00%	21.00%	35.00%
State taxes, net of federal benefit	2.60%	4.70%	3.30%
Impact of 2017 tax reform on deferred tax balance	0.00%	0.00%	4.60%
Equity-based compensation expense	(0.40%)	(1.50%)	(0.80%)
Contingent consideration	0.00%	7.20%	4.40%
In-process research and development	(3.40%)	0.00%	0.00%
Other permanent items, net	(0.40%)	(1.40%)	(0.50%)
Tax credits	0.40%	6.20%	0.70%
Valuation allowance	(19.80%)	(67.40%)	(0.80%)
Other, net	0.00%	0.60%	0.20%
Effective tax rate	0.00%	(30.60%)	46.10%