SHARE BASED COMPENSATION - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Weighted Average Exercise Price
Number of shares exercisable (in shares) | shares	5,400,000
Weighted average exercise price (in dollars per share) | $ / shares	$ 19.34
Stock Options
Shares Underlying Options
Beginning balance (in shares) | shares	7,371,733
Granted (in shares) | shares	1,497,375
Exercised (in shares) | shares	(103,270)
Forfeited/canceled (in shares) | shares	(394,340)
Ending balance (in shares) | shares	8,371,498	7,371,733
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 19.52
Granted (in dollars per share) | $ / shares
Exercised (in dollars per share) | $ / shares
Forfeited/canceled (in dollars per share) | $ / shares
Ending balance (in dollars per share) | $ / shares	$ 18.95	$ 19.52
Weighted average remaining contractual life (years)	6 years 6 months 29 days	6 years 7 months 17 days
Aggregate intrinsic value | $	$ 17,968	$ 4,906
Unamortized stock compensation expense | $	$ 28,900
Weighted-average recognition period (in years)	2 years 7 months 6 days