STOCK-BASED COMPENSATION (Equity Based Compensation Schedule) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Allocation of stock-based compensation expense
Stock compensation expense	$ 693	$ 358
Research and development expenses
Allocation of stock-based compensation expense
Stock compensation expense	252	149
Research and development expenses | Employees
Allocation of stock-based compensation expense
Stock compensation expense	226	144
Research and development expenses | Non-employees
Allocation of stock-based compensation expense
Stock compensation expense	26	5
General and administrative expenses
Allocation of stock-based compensation expense
Stock compensation expense	441	209
General and administrative expenses | Employees and directors
Allocation of stock-based compensation expense
Stock compensation expense	367	203
General and administrative expenses | Non-employees
Allocation of stock-based compensation expense
Stock compensation expense	$ 74	$ 6