INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	$ 133,000
Aggregate limitation on utilization of certain net operating losses and credits	4,600
Tax credit write off	2,800
Gross deferred tax assets	$ (46,240)	$ (33,136)
Valuation allowance percent	100.00%	100.00%
Increase in valuation allowance	$ (13,100)	$ (10,600)
Research and experimentation tax carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward amount	$ 10,800