Marketable Investments - Summary of Maturity Periods of the Marketable Securities (Detail) - Corporate Obligations [Member] - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
FY 2016	$ 9,071
FY 2017	34,789
FY 2018	13,813
Total	$ 57,673	$ 47,775