| Fair Value Measurements - Warrant Derivative Liability (Activity in Level 3) (Details) | 6 Months Ended | 
|---|---|
| Oct. 31, 2016  USD ($) | |
| Fair Value Measurements - Warrant Derivative Liability Activity In Level 3 Details | |
| Balance April 30, 2016 | |
| Initial valuation in valuation of warrant derivative liability | 52,500 | 
| Change in valuation of warrant derivative liability | |
| Balance October 31, 2016 | $ 52,500 | 
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- References No definition available. 
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- Definition Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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