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Common Stock Warrants - Summary of Common Stock Warrants Outstanding (Details) - $ / shares | 6 Months Ended |  |
--- | --- | --- | ---
Jun. 30, 2017 | Dec. 31, 2016 | Mar. 31, 2012
Class Of Warrant Or Right [Line Items] |  |  |
Warrant outstanding (in shares) | 19,279 | 498,556 |
Five Year Warrants Issued in March 2012 [Member] |  |  |
Class Of Warrant Or Right [Line Items] |  |  |
Exercise price of warrants (in dollars per share) |  |  | $ 35.20
Five Year Warrants Issued in March 2012 [Member] | Contingent Warrant Liability [Member] |  |  |
Class Of Warrant Or Right [Line Items] |  |  |
Issuance Date | 2012-03 |  |
Expiration Date | 2017-03 |  |
Exercise price of warrants (in dollars per share) | $ 35.20 |  |
Warrant outstanding (in shares) |  | 479,277 |
Five Year Warrants Issued in September 2012 [Member] | Stockholders' Deficit [Member] |  |  |
Class Of Warrant Or Right [Line Items] |  |  |
Issuance Date | 2012-09 |  |
Expiration Date | 2017-09 |  |
Exercise price of warrants (in dollars per share) | $ 70.80 |  |
Warrant outstanding (in shares) | 1,967 | 1,967 |
Five Year Warrants Issued in February 2015 [Member] | Stockholders' Deficit [Member] |  |  |
Class Of Warrant Or Right [Line Items] |  |  |
Issuance Date | 2015-02 |  |
Expiration Date | 2020-02 |  |
Exercise price of warrants (in dollars per share) | $ 66.20 |  |
Warrant outstanding (in shares) | 9,063 | 9,063 |
Five Year Warrants Issued in February 2016 [Member] | Stockholders' Deficit [Member] |  |  |
Class Of Warrant Or Right [Line Items] |  |  |
Issuance Date | 2016-02 |  |
Expiration Date | 2021-02 |  |
Exercise price of warrants (in dollars per share) | $ 15.40 |  |
Warrant outstanding (in shares) | 8,249 | 8,249 |

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- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(4)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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- Definition Number of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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