Summary of Significant Accounting Policies - Summary of Components of Marketable Securities (Details) - USD ($) $ in Thousands |
Sep. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Amortized Cost | $ 6,890 | $ 18,843 |
| Unrealized Losses | (24) | (78) |
| Market Value | 6,866 | 18,765 |
| U.S. Treasuries [Member] | ||
| Amortized Cost | 2,578 | 1,744 |
| Unrealized Losses | (3) | |
| Market Value | 2,575 | 1,744 |
| Corporate Bonds [Member] | ||
| Amortized Cost | 4,312 | 17,099 |
| Unrealized Losses | (21) | (78) |
| Market Value | $ 4,291 | $ 17,021 |
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- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of investment in marketable security, classified as current. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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