STOCK-BASED COMPENSATION (Equity Based Compensation Schedule) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Allocation of stock-based compensation expense
Stock compensation expense	$ 1,611	$ 1,457	$ 2,990	$ 2,811
Research and development expenses
Allocation of stock-based compensation expense
Stock compensation expense	870	690	1,518	1,323
General and administrative expenses
Allocation of stock-based compensation expense
Stock compensation expense	$ 741	$ 767	$ 1,472	$ 1,488