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           Warrants - Additional Information (Detail) (USD $) 
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        0 Months Ended | 3 Months Ended | 12 Months Ended | 
|---|---|---|---|
| 
           Mar. 23, 2015 
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           Mar. 31, 2015 
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           Dec. 31, 2014 
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| Equity [Abstract] | |||
| Shares underlying warrant outstanding | 2,170,925ogen_ClassOfWarrantExpired | 2,170,925ogen_ClassOfWarrantExpired | 5,000ogen_ClassOfWarrantExpired | 
| Warrants exercisable price per share | $ 2.00ogen_ClassOfWarrantExpiredWeightedAverageExercisePrice | $ 2.00ogen_ClassOfWarrantExpiredWeightedAverageExercisePrice | $ 10.00ogen_ClassOfWarrantExpiredWeightedAverageExercisePrice | 
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- Definition 
          Number of warrants expired in period. No definition available. 
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| X | ||||||||||
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- Definition 
          Weighted average exercise price of warrants expired in period. No definition available. 
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- Details 
          
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