Income Taxes - Additional Information (Detail) - USD ($) |
3 Months Ended | 9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Dec. 31, 2017 |
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| Income Tax Disclosure [Abstract] | |||||
| Liability for unrecognized tax benefit, including related estimates of penalties and interest | $ 0 | $ 0 | $ 0 | $ 0 | |
| Income tax provision (benefit) | $ 49,000 | $ 35,000 | $ 91,000 | $ 111,000 | |
| Projected annual effective tax rate | 0.50% | 0.80% | 0.60% | 0.90% | |
| Statutory tax rate | 21.00% | 34.00% | |||
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- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- References No definition available.
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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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- Definition Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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