INCOME TAXES - Provision (benefit) for income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 0	$ (151)	$ 0
State	(261)	(91)	(383)
Foreign	1,456	1,663	2,652
Subtotal	1,195	1,421	2,269
Deferred:
Federal	0	0	(268)
State	0	0	(21)
Foreign	(462)	(1,185)	(819)
Subtotal	(462)	(1,185)	(1,108)
Income tax provision	$ 733	$ 236	$ 1,161