Summary of Significant Accounting Policies - Summary of Components of Marketable Securities (Details) - USD ($) $ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Amortized cost | $ 18,687 | |
| Unrealized gain | ||
| Unrealized loss | (78) | |
| Market value | 18,765 | |
| U.S. Government Obligations [Member] | ||
| Amortized cost | 1,744 | |
| Unrealized gain | ||
| Unrealized loss | ||
| Market value | 1,744 | |
| Corporate Bonds [Member] | ||
| Amortized cost | 16,943 | |
| Unrealized gain | ||
| Unrealized loss | (78) | |
| Market value | $ 17,021 |
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of investments in debt and equity securities, including, but not limited to, held-to-maturity, trading and available-for-sale expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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