STOCK-BASED COMPENSATION - Options (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Feb. 27, 2017
Stock options and restricted stock units granted under the 2017 Plan
Stock reserved for future issuance	0
Granted (in units)	2,150,400
Restricted stock unit grants under the Plan
# of Restricted Stock Units Granted	2,150,400
Issued and outstanding	2,150,400
Stock Option
Stock options and restricted stock units granted under the 2017 Plan
Granted (in shares)	1,402,000
Stock option grants under the Plan
# of Options Granted	1,402,000
Granted (in shares)	1,402,000
Performance Stock Units
Stock options and restricted stock units granted under the 2017 Plan
Granted (in units)	1,761,900
Restricted stock unit grants under the Plan
# of Restricted Stock Units Granted	1,761,900
2017 Omnibus Incentive Plan
Stock options and restricted stock units granted under the 2017 Plan
Number of shares authorized			4,500,000
Stock reserved for future issuance	0
2017 Omnibus Incentive Plan | Minimum
Stock option grants under the Plan
Vesting Period (in years)	3 years
Restricted stock unit grants under the Plan
Vesting Period (in years)	3 years
2017 Omnibus Incentive Plan | Maximum
Stock option grants under the Plan
Vesting Period (in years)	5 years
Restricted stock unit grants under the Plan
Vesting Period (in years)	5 years
2017 Omnibus Incentive Plan | Director Group | Minimum
Stock option grants under the Plan
Vesting Period (in years)	1 year
Restricted stock unit grants under the Plan
Vesting Period (in years)	1 year
2017 Omnibus Incentive Plan | Director Group | Maximum
Stock option grants under the Plan
Vesting Period (in years)	5 years
Restricted stock unit grants under the Plan
Vesting Period (in years)	5 years
2017 Omnibus Incentive Plan | Stock Option
Stock options and restricted stock units granted under the 2017 Plan
Granted (in shares)	1,811,900
Stock option grants under the Plan
# of Options Granted	1,811,900
Issued and Outstanding (in shares)	4,058,624	2,308,924
Weighted Average Exercise Price (in dollars per share)	$ 1.41
Granted (in shares)	1,811,900
2017 Omnibus Incentive Plan | Stock Option | Director Group
Stock options and restricted stock units granted under the 2017 Plan
Granted (in shares)	150,000
Stock option grants under the Plan
# of Options Granted	150,000
Issued and Outstanding (in shares)	100,000
Vesting Period (in years)	5 years
Weighted Average Exercise Price (in dollars per share)	$ 9.98
Weighted Average Grant Date Fair Value (in dollars)	$ 4.36
Granted (in shares)	150,000
Restricted stock unit grants under the Plan
Vesting Period (in years)	5 years
2017 Omnibus Incentive Plan | Stock Option | Employee Group
Stock options and restricted stock units granted under the 2017 Plan
Granted (in shares)	4,444,630
Stock option grants under the Plan
# of Options Granted	4,444,630
Issued and Outstanding (in shares)	3,958,624
Weighted Average Exercise Price (in dollars per share)	$ 5.65
Weighted Average Grant Date Fair Value (in dollars)	$ 2.44
Granted (in shares)	4,444,630
2017 Omnibus Incentive Plan | Stock Option | Employee Group | Minimum
Stock option grants under the Plan
Vesting Period (in years)	3 years
Restricted stock unit grants under the Plan
Vesting Period (in years)	3 years
2017 Omnibus Incentive Plan | Stock Option | Employee Group | Maximum
Stock option grants under the Plan
Vesting Period (in years)	5 years
Restricted stock unit grants under the Plan
Vesting Period (in years)	5 years
2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs)
Stock options and restricted stock units granted under the 2017 Plan
Granted (in units)	108,498
Restricted stock unit grants under the Plan
# of Restricted Stock Units Granted	108,498
Issued and outstanding	1,066,501	1,180,882
2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs) | Director Group
Stock options and restricted stock units granted under the 2017 Plan
Granted (in units)	893,996
Restricted stock unit grants under the Plan
# of Restricted Stock Units Granted	893,996
Issued and outstanding	772,784
Weighted Average Grant Date Fair Value	$ 2.75
2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs) | Director Group | Minimum
Stock option grants under the Plan
Vesting Period (in years)	1 year
Restricted stock unit grants under the Plan
Vesting Period (in years)	1 year
2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs) | Director Group | Maximum
Stock option grants under the Plan
Vesting Period (in years)	2 years
Restricted stock unit grants under the Plan
Vesting Period (in years)	2 years
2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs) | Employee Group
Stock options and restricted stock units granted under the 2017 Plan
Granted (in units)	1,568,655
Stock option grants under the Plan
Vesting Period (in years)	5 years
Restricted stock unit grants under the Plan
# of Restricted Stock Units Granted	1,568,655
Issued and outstanding	293,717
Vesting Period (in years)	5 years
Weighted Average Grant Date Fair Value	$ 10.59