RESTRUCTURING, COSTS BY CATEGORY (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Restructuring costs by category
Restructuring costs, cash	$ 857
Restructuring costs, non cash	41
Restructuring costs	898
Research and development
Restructuring costs by category
Restructuring costs, cash	669
Restructuring costs, non cash	41
Restructuring costs	710
General and administrative
Restructuring costs by category
Restructuring costs, cash	188
Restructuring costs	$ 188