ACQUISITION - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011
Business Acquisition [Line Items]
Business acquisition, present value of contingent consideration	$ 4,626,000
Voxel Holdings Incorporated
Business Acquisition [Line Items]
Business acquisition, total purchase price	33,300,000
Business acquisition, accrued contingent consideration	5,000,000
Business acquisition, present value of contingent consideration	4,626,000
Business acquisition, contingent consideration payable expected delivery date	Dec. 30, 2013
Business acquisition, acquisition-related expenses	$ 600,000