Annual report pursuant to Section 13 and 15(d)

Stock Option and Purchase Plans - Summary of Weighted Average Exercise Prices and Contractual Lives for Outstanding and Exercisable Stock Options (Detail)

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Stock Option and Purchase Plans - Summary of Weighted Average Exercise Prices and Contractual Lives for Outstanding and Exercisable Stock Options (Detail) (USD $)
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2013
Range One [Member]
Dec. 31, 2013
Range Two [Member]
Dec. 31, 2013
Range Three [Member]
Dec. 31, 2013
Range Four [Member]
Dec. 31, 2013
Range Five [Member]
Dec. 31, 2013
Range Six [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Exercise Price Lower Range         $ 2.68 $ 4.84 $ 9.15 $ 14.01 $ 41.40  
Exercise Price Upper Range         $ 3.45 $ 7.07 $ 10.07 $ 24.88 $ 51.93  
Outstanding, Shares 1,409,777 1,521,275 1,661,445 1,904,232 265,404 578,364 141,975 372,314 51,720 1,409,777
Outstanding, Weighted Average Remaining Life in Years         10 months 24 days 4 years 8 months 12 days 3 years 2 months 12 days 7 years 6 months 9 years 10 months 24 days 4 years 9 months 18 days
Outstanding, Weighted Average Exercise Price $ 10.44 $ 8.23 $ 6.71 $ 5.58 $ 3.07 $ 5.34 $ 9.35 $ 18.62 $ 49.49 $ 10.44
Exercisable, Shares 1,149,532 1,168,459 1,280,744   265,404 533,109 141,975 209,044    1,149,532
Exercisable, Weighted Average Remaining Life in Years         10 months 24 days 4 years 7 months 6 days 3 years 2 months 12 days 6 years 10 months 24 days   4 years
Exercisable, Weighted Average Exercise Price $ 7.81 $ 6.72 $ 5.47   $ 3.07 $ 5.35 $ 9.35 $ 19.08   $ 7.81