SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost, Total	$ 5,846	$ 4,104
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost, Total	2,701	2,000
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost, Total	$ 3,145	$ 2,104