INCOME TAXES - Tax credit carryforwards (Details) $ in Thousands	Sep. 30, 2016 USD ($)
U.S.
Income tax credit carryforwards
Income tax credit carryforward	$ 8,200
U.S. | Foreign Tax Credits
Income tax credit carryforwards
Income tax credit carryforward	4,818
U.S. | Research and Development Tax Credits
Income tax credit carryforwards
Income tax credit carryforward	3,405
State
Income tax credit carryforwards
Income tax credit carryforward	17,900
State | Research and Development Tax Credits
Income tax credit carryforwards
Income tax credit carryforward	$ 17,911