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v3.19.1

Summary of Significant Accounting Policies - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Assets: |  |
Money market funds, fair value | $ 4,747 | $ 9,711
Liabilities: |  |
Warrant liability, fair value | 10 | 2,512
Quoted Prices in Active Markets (Level 1) [Member] |  |
Assets: |  |
Money market funds, fair value | 4,747 | 9,711
Significant Unobservable Inputs (Level 3) [Member] |  |
Liabilities: |  |
Warrant liability, fair value | $ 10 | $ 2,512

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