Income Taxes - Geographical Distribution of Income (Loss) before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ (11,830)	$ (13,707)
Foreign	(11)	(17)
Income (loss) before income taxes	(11,841)	(13,724)
Income (loss) resulting from discontinued operations	$ (1,494)	$ (3,593)

Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
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-Section 50
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The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

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-Publisher FASB
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The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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