INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Income tax expense (benefit)		$ (5,283)	$ 1,067	$ (1,429)
Tax rate changes	$ 25,500	0	0	27,560
Valuation allowance for deferred tax assets		90,820	41,905
Increase (decrease) in valuation allowance		48,900	(12,300)	$ 9,000
Accrued interest and penalties associated with unrecognized tax benefits		400
Unrecognized tax benefit that would affect the effective tax rate		4,000	$ 16,100
State
Tax Credit Carryforward [Line Items]
Net operating loss carry forwards		74,900
State | Research and development tax credits
Tax Credit Carryforward [Line Items]
Tax credit carryforwards		2,400
Federal
Tax Credit Carryforward [Line Items]
Net operating loss carry forwards		$ 3,700