RESTRUCTURING AND OTHER CHARGES - Summary of Changes in Restructuring Accrual (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	$ 1,103	$ 3,605	$ 2,743
Restructuring charges	412	3,662	5,070
Payments	(1,097)	(6,127)	(4,084)
Long-lived assets write-off			(230)
Reserve adjustments	(52)	(37)	106
Restructuring Reserve - Ending Balance	400	1,103	3,605
Employee severance costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	0	2,005	82
Restructuring charges	506	2,413	4,011
Payments	(358)	(4,406)	(2,190)
Long-lived assets write-off			0
Reserve adjustments	(20)	(12)	102
Restructuring Reserve - Ending Balance	128	0	2,005
Contract termination costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	1,103	1,600	2,661
Restructuring charges	(94)	825	355
Payments	(739)	(1,322)	(1,420)
Long-lived assets write-off			0
Reserve adjustments	(32)	0	4
Restructuring Reserve - Ending Balance	238	1,103	1,600
Other costs
Restructuring Reserve [Roll Forward]
Restructuring Reserve - Beginning Balance	0	0	0
Restructuring charges	0	424	704	[1]
Payments	0	(399)	(474)
Long-lived assets write-off			(230)	[1]
Reserve adjustments	0	(25)	0
Restructuring Reserve - Ending Balance	$ 0	$ 0	$ 0

[1] $0.2 million charge related to impairment of property and equipment resulting from the transfer of our research, development and prototype production of the Millios system to our facility in Dornstadt, Germany and the consolidation of global manufacturing in our facility in Fremont, California.