ACQUISITION - Summary of intangible assets acquired(Details 1) (Voxel Holdings Inc, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, fair value	$ 15,700
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, fair value	7,800
Intangible assets, weighted average useful life	10 years
Internally used software
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, fair value	3,400
Intangible assets, weighted average useful life	5 years
Acquired technology
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, fair value	4,300
Intangible assets, weighted average useful life	8 years
Trade Names
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, fair value	$ 200
Intangible assets, weighted average useful life	10 years