| Income Taxes - Summary of Components of Provision for Income Taxes (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | |
| Current | |||
| U.S. | $ 444 | $ 472 | $ 444 | 
| Total Current | 444 | 472 | 444 | 
| Deferred | |||
| Income Tax Provision | $ 444 | $ 472 | $ 444 | 
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- Definition Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
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- Definition Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
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- References No definition available. 
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- References No definition available. 
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| X | ||||||||||
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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