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Marketable Securities and Fair Value Disclosures (Tables) | 12 Months Ended
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Dec. 31, 2017
Marketable Securities And Fair Value Disclosures [Abstract] |
Summary of Marketable Securities | Marketable securities consisted of the following as of December 31, 2017 and 2016 (in thousands):
| December 31, 2017 |
|  |  |  |  | Gross |  |  | Gross |  |  |  |  |
| Amortized |  |  | Unrealized |  |  | Unrealized |  |  | Fair |
| Cost |  |  | Gains |  |  | Losses |  |  | Value |
Short-term available-for-sale securities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate bonds | $ | 3,052 |  |  | $ | — |  |  | $ | (2 | ) |  | $ | 3,050 |
Total | $ | 3,052 |  |  | $ | — |  |  | $ | (2 | ) |  | $ | 3,050 |
| December 31, 2016 |
|  |  |  |  | Gross |  |  | Gross |  |  |  |  |
| Amortized |  |  | Unrealized |  |  | Unrealized |  |  | Fair |
| Cost |  |  | Gains |  |  | Losses |  |  | Value |
Short-term available-for-sale securities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate bonds | $ | 13,778 |  |  | $ | — |  |  | $ | (16 | ) |  | $ | 13,762 |
Total | $ | 13,778 |  |  | $ | — |  |  | $ | (16 | ) |  | $ | 13,762 |
Long-term available-for-sale securities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate bonds | $ | 2,355 |  |  | $ | 3 |  |  | $ | (6 | ) |  | $ | 2,352 |
Total | $ | 2,355 |  |  | $ | 3 |  |  | $ | (6 | ) |  | $ | 2,352 |
Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturity | As of December 31, 2017, the amortized cost and estimated fair value of available-for-sale securities by contractual maturity were as follows (in thousands):
| Amortized |  |  | Fair |
| Cost |  |  | Value |
Due in one year or less | $ | 3,052 |  |  | $ | 3,050 |
Total | $ | 3,052 |  |  | $ | 3,050 |
Summary of Assets Measured at Fair Value on Recurring Basis | The following table identifies the Company’s assets that were measured at fair value on a recurring basis (in thousands):
| Balance |  |  | Level 1 |  |  | Level 2 |  |  | Level 3 |
December 31, 2017 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Money market | $ | 8,189 |  |  | $ | 8,189 |  |  | $ | — |  |  | $ | — |
Corporate bonds |  | 3,725 |  |  |  | — |  |  |  | 3,725 |  |  |  | — |
Total | $ | 11,914 |  |  | $ | 8,189 |  |  | $ | 3,725 |  |  | $ | — |
December 31, 2016 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Money market | $ | 7,672 |  |  | $ | 7,672 |  |  | $ | — |  |  | $ | — |
Corporate bonds |  | 16,114 |  |  |  | — |  |  |  | 16,114 |  |  |  | — |
Total | $ | 23,786 |  |  | $ | 7,672 |  |  | $ | 16,114 |  |  | $ | — |

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- Definition Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19190-110258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments. + References No definition available. + Details
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- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
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