ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accounts payable	$ 8,531	$ 4,344
Accrued clinical expense	10,154	5,412
Accrued development and other expense	1,243	867
Accrued compensation and benefits	5,847	3,021
Total accounts payable and accrued liabilities	25,775	13,644
Long-term liabilities	732	314
Noncurrent deferred revenue	100
Other liabilities	$ 600	$ 300