ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
ACCRUED LIABILITIES
Accrued compensation	$ 7,345	$ 11,730
Accrued royalties	17,370	21,703
Accrued restructuring and one-time termination costs	9,483
Other accrued liabilities	26,298	25,965
Total accrued liabilities	$ 60,496	$ 59,398