Marketable Securities and Fair Value - Summary of Company's Available-for-Sale Securities (Detail) - USD ($) $ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Schedule Of Available For Sale Securities [Line Items] | ||
| Cost Basis | $ 0 | $ 0 |
| Unrealized Gain | 0 | 0 |
| Unrealized Loss | 0 | 0 |
| Fair Value | 0 | 0 |
| Money Market Funds | ||
| Schedule Of Available For Sale Securities [Line Items] | ||
| Cost Basis | 51,751 | 796 |
| Unrealized Gain | 0 | 0 |
| Unrealized Loss | 0 | 0 |
| Fair Value | 51,751 | 796 |
| Less Cash Equivalents | ||
| Schedule Of Available For Sale Securities [Line Items] | ||
| Cost Basis | 51,751 | 796 |
| Unrealized Gain | 0 | 0 |
| Unrealized Loss | 0 | 0 |
| Fair Value | $ 51,751 | $ 796 |
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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity 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 and equity 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 and equity 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 Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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