Fair Value Measurements - Summary of Cash and Cash Equivalents and Short Term Investments (Detail) - USD ($) $ in Thousands |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
| Cash, amortized cost and estimated fair value | $ 1,070 | $ 1,262 |
| Cash and cash equivalents, amortized cost and estimated fair value | 9,515 | 5,284 |
| Restricted cash, amortized cost and estimated fair value | 50 | 272 |
| Short-term investments, amortized cost and estimated fair value | 5,089 | |
| Money market securities [Member] | ||
| Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
| Cash equivalents, amortized cost and estimated fair value | 8,445 | 4,022 |
| Restricted cash, amortized cost and estimated fair value | 50 | $ 272 |
| Corporate bonds and commercial paper [Member] | ||
| Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
| Short-term investments, amortized cost and estimated fair value | $ 5,089 |
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- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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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- Definition Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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