| Fair Value Measurements - Warrant Derivative Liability (Narrative) (Details) - Warrants With Price Protection [Member] | Jan. 31, 2017  $ / shares  shares | 
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| Number of warrants containing price protection | shares | 62,500 | 
| Redemption value | $ / shares | $ 0.84 | 
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- Definition Exercise price per share or per unit of warrants or rights outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Number of warrants or rights outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
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