Marketable Securities - Schedule of Estimated Fair Value of Investments by Contractual Maturity (Details) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Investments Debt And Equity Securities [Abstract] | ||
| Due within one year | $ 24,334 | $ 325 |
| Total | $ 24,334 | $ 325 |