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Fair Value (Tables) | 12 Months Ended
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Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |
Schedule of Estimated Fair Value Determined Using Option Pricing Model Assumptions |
|  | As of December 31, 2019 |  |  | As of December 31, 2018 |
Expected term |  | 1.1 years |  |  | 2.1 years |
Common stock market price |  | $ | 2.40 |  |  | $ | 14.50 |
Risk-free interest rate |  |  | 1.59 | % |  |  | 2.48 | %
Expected volatility |  |  | 168 | % |  |  | 125 | %
Resulting fair value (per warrant) |  | $ | 1.47 |  |  | $ | 6.50 |
Summary of Change in Level 3 Warrant Liability Value | The following table summarizes the change in our Level 3 warrant liability value (in thousands):
|  | Years ended December 31, |
Warrant liability |  | 2019 |  |  | 2018 |
Beginning balance |  | $ | 916 |  |  | $ | 3,148 |
Issuance of warrants |  |  | 10,214 |  |  |  | — |
Exercises |  |  | (794 | ) |  |  | — |
Change in fair value |  |  | (3,407 | ) |  |  | (2,233 | )
Ending balance |  | $ | 6,929 |  |  | $ | 916 |
Fair Value and Carrying Value of Term Loan | At December 31, 2019 and 2018, the aggregate fair value and the carrying value of the Company’s term loan were as follows (in thousands):
|  | December 31, 2019 |  |  | December 31, 2018 |
|  | Fair Value |  |  | Carrying Value |  |  | Fair Value |  |  | Carrying Value |
Debt |  | $ | 10,761 |  |  | $ | 11,060 |  |  | $ | 14,043 |  |  | $ | 14,202 |
Series T Warrants [Member] |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |
Schedule of Estimated Fair Value Determined Using Option Pricing Model Assumptions | The Series T Warrants are not traded in an active securities market, and as such the estimated the fair value as of December 31, 2019 and 2018 was determined by using an option pricing model with the following assumptions:
|  | As of December 31, 2019 |  |  | As of December 31, 2018 |
Expected term |  | 1.1 years |  |  | 2.1 years |
Common stock market price |  | $ | 2.40 |  |  | $ | 14.50 |
Risk-free interest rate |  |  | 1.59 | % |  |  | 2.48 | %
Expected volatility |  |  | 168 | % |  |  | 125 | %
Resulting fair value (per warrant) |  | $ | 1.47 |  |  | $ | 6.50 |
Series U Warrants [Member] |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |
Schedule of Estimated Fair Value Determined Using Option Pricing Model Assumptions | The Series U warrants will be marked to market as of each balance sheet date until they are exercised or upon expiration, with the changes in fair value recorded as non-operating income or loss in the statement of operations and comprehensive income (loss).
|  | As of December 31, 2019 |  |  | As of September 25, 2019 |
Expected term |  | 4.75 years |  |  | 5 years |
Common stock market price |  | $ | 2.40 |  |  | $ | 3.42 |
Risk-free interest rate |  |  | 1.68 | % |  |  | 1.60 | %
Expected volatility |  |  | 134.5 | % |  |  | 134.9 | %
Resulting fair value (per warrant) |  | $ | 1.94 |  |  | $ | 2.90 |

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- Definition Tabular disclosure of input and valuation technique used to measure fair value and change in valuation approach and technique used to measure similar asset in prior period by class of asset or liability on non-recurring basis. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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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. + References No definition available. + Details
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- Definition Tabular disclosure of the fair value of financial instruments, including financial assets and financial liabilities, and the measurements of those instruments, assets, and liabilities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13467-108611 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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- Definition Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19279-110258 + Details
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