STOCK-BASED COMPENSATION (Equity Based Compensation Schedule) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Allocation of stock-based compensation expense
Stock compensation expense	$ 1,389	$ 1,368	$ 4,200	$ 3,958
Research and development expenses
Allocation of stock-based compensation expense
Stock compensation expense	703	686	2,026	2,033
General and administrative expenses
Allocation of stock-based compensation expense
Stock compensation expense	$ 686	$ 682	$ 2,174	$ 1,925