Marketable Investments - Summary of Maturity Periods of the Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Trading Securities And Other Trading Assets [Line Items]
Total	$ 47,775	$ 54,885
Corporate Obligations [Member]
Schedule Of Trading Securities And Other Trading Assets [Line Items]
FY 2016	19,305
FY 2017	23,490
FY 2018	4,980
Total	$ 47,775	$ 54,885