Marketable Securities and Fair Value - Additional Information (Detail) - USD ($) shares in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
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| Schedule Of Available For Sale Securities [Line Items] | ||||
| Realized gain or losses | $ 0 | $ 0 | $ 0 | $ 0 |
| Weighted average maturity for available for sale securities | 1 month | |||
| Marketable securities with unrealized loss positions | $ 0 | $ 0 | ||
| Shares of common stock to be purchased with warrants | 8.3 | 8.3 | ||
| Maximum | ||||
| Schedule Of Available For Sale Securities [Line Items] | ||||
| Available for sale securities, longest maturity date | 2017-07 | |||
| X | ||||||||||
- Definition Available for sale securities, longest maturity date No definition available.
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| X | ||||||||||
- Definition Weighted average maturity for available for sale securities. No definition available.
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| X | ||||||||||
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Number of warrants or rights outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- 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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| X | ||||||||||
- Details
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