Marketable Securities - Additional Information (Details) $ in Thousands |
3 Months Ended |
|---|---|
|
Mar. 31, 2018
USD ($)
| |
| Investments Debt And Equity Securities [Abstract] | |
| Available-for sale securities maximum remaining contractual maturity | 2 years |
| Realized gains or losses on available-for-sale securities | $ 0 |