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Stockholders' Equity - Preferred Stock (Details) - $ / shares | 1 Months Ended | 12 Months Ended
--- | --- | ---
Apr. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2020 | Dec. 31, 2019
Preferred Stock [Abstract] |  |  |  |
Preferred stock, shares authorized (in shares) |  |  | 5,000,000 | 5,000,000
Preferred stock, par value (in dollars per share) |  |  | $ 0.001 | $ 0.001
Preferred stock, shares outstanding (in shares) |  |  | 1,954 | 1,959
Series A Convertible Preferred Stock [Member] |  |  |  |
Preferred Stock [Abstract] |  |  |  |
Preferred stock, shares outstanding (in shares) |  |  | 0 | 0
Convertible preferred stock |  |  | 3.60% | 3.60%
Series B Convertible Preferred Stock [Member] |  |  |  |
Preferred Stock [Abstract] |  |  |  |
Preferred stock, shares outstanding (in shares) |  |  | 1,016 | 1,021
Series B Convertible Preferred Stock [Member] | 2018 Rights Offering [Member] |  |  |  |
Preferred Stock [Abstract] |  |  |  |
Preferred stock, shares outstanding (in shares) |  |  | 1,016 |
Number of preferred stock, shares converted |  |  | 6,096 |
Series C Convertible Preferred Stock [Member] |  |  |  |
Preferred Stock [Abstract] |  |  |  |
Preferred stock, shares outstanding (in shares) |  |  | 938 | 938
Conversion Price Per Share | $ 3.2132 | $ 3.2132 |  | $ 39.93
Preferred stock conversion price reduced (in dollars per share) | $ 2.25 | $ 7.50 |  | $ 7.50
Series C Convertible Preferred Stock [Member] | 2018 Rights Offering [Member] |  |  |  |
Preferred Stock [Abstract] |  |  |  |
Preferred stock, shares outstanding (in shares) |  |  | 938 |
Number of preferred stock, shares converted |  |  | 416,889 |

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- Definition Conversion price per share. + References No definition available. + Details
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- Definition Number Of Preferred Stock Shares Exercised. + References No definition available. + Details
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- Definition Preferred Stock [Abstract] + References No definition available. + Details
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- Definition Per share decrease in conversion price of convertible preferred stock. Excludes change due to standard antidilution provision. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 + Details
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- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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