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Commitments and Contingencies - Additional Information (Detail) (USD $)
1 Months Ended 12 Months Ended
Jul. 31, 2010
Patents
Dec. 31, 2009
Respondent
Sep. 30, 2009
Respondent
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Commitment And Contingencies [Line Items]            
Purchase order outstanding       $ 7,156,000    
Total annual rental expense       5,806,000 5,557,000 5,190,000
Total annual rental income       $ 854,000 $ 791,000 $ 607,000
Number of respondents with whom a settlement was reached   5 2      
Number of the Company's patents found invalid 2