Annual report pursuant to Section 13 and 15(d)

Marketable Securities - Additional Information (Detail)

v3.6.0.2
Marketable Securities - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Investments Debt And Equity Securities [Abstract]      
Investments maturity period 1 year    
Realized losses of available-for-sale securities $ 0 $ 0 $ 0
Investments other-than-temporarily impaired $ 0 $ 0 $ 0