Marketable Investments - Summary of Maturity Periods of the Marketable Securities (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Schedule of Available-for-sale Securities [Line Items] | ||
| FY 2017 | $ 37,159 | |
| FY 2018 | 23,988 | |
| Total | 61,147 | $ 47,775 |
| Federal Agency Obligations [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| FY 2018 | 1,793 | |
| Total | 1,793 | |
| Corporate Obligations [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| FY 2017 | 37,159 | |
| FY 2018 | 22,195 | |
| Total | $ 59,354 | $ 47,775 |