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Balance Sheet Components - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]              
Cash and cash equivalents $ 198,283,000 $ 198,283,000 $ 200,184,000 $ 198,283,000 $ 200,184,000 $ 153,324,000 $ 165,455,000
Contractual maturities of available-for-sale investments 3 years            
Other-than-temporary impairment loss   0 $ 0 0 $ 0    
Foreign subsidiaries [Member]              
Schedule of Available-for-sale Securities [Line Items]              
Cash and cash equivalents $ 25,000,000 $ 25,000,000   $ 25,000,000