STOCK-BASED COMPENSATION - RSA activity (Details) - Restricted Stock [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unvested, Shares, Outstanding, Beginning of period	352	192	117
Unvested Shares, Granted	541	305	122
Unvested Shares, Vested	(125)	(127)	(42)
Unvested Shares, Forfeited	(61)	(18)	(5)
Unvested Shares, Outstanding, End of period	707	352	192	117
Weighted Average Grant Date Fair Value, Outstanding, Beginning of period	$ 48.14	$ 61.46	$ 54.04
Weighted Average Grant Date Fair Value, Granted	33.02	44.42	66.39
Weighted Average Grant Date Fair Value, Vested	48.32	58.88	54.77
Weighted Average Grant Date Fair Value, Forfeited	48.16	51.53	62.63
Weighted Average Grant Date Fair Value, Outstanding, End of period	$ 36.52	$ 48.14	$ 61.46	$ 54.04
Weighted Average Remaining Term (years)	2 years 9 months 18 days	2 years 8 months 12 days	2 years 7 months 6 days	2 years 1 month 6 days
Unrecognized non-option costs	$ 19.8
Period of cost recognition	2 years 9 months 18 days
Employees and Consultants [Member]
Vesting period	4 years
Non Employee Director [Member]
Vesting period	1 year