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           Basis of Presentation - Additional Information (Detail) (USD $) 
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        3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
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           Mar. 31, 2015 
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           Mar. 31, 2014 
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           Dec. 31, 2013 
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           Dec. 31, 2014 
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| Organization, Consolidation and Presentation of Financial Statements [Abstract] | ||||
| Revenues generated by company | $ 363,774us-gaap_Revenues | $ 214,660us-gaap_Revenues | ||
| Net loss | 1,292,777us-gaap_NetIncomeLoss | 1,640,884us-gaap_NetIncomeLoss | ||
| Cash used in operations | 1,288,371us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations | 1,584,248us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations | ||
| Accumulated deficit | 77,237,412us-gaap_RetainedEarningsAccumulatedDeficit | 75,944,635us-gaap_RetainedEarningsAccumulatedDeficit | ||
| Gross proceeds from issuance of common stock | 3,900,000ogen_ProceedsFromIssuanceOfCommonStockGross | |||
| Net proceeds from issuance of common stock | $ 9,904,996ogen_ProceedsFromIssuanceOfCommonStockNetOfOfferingCost | |||
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- Definition 
          The gross amount of cash inflow from the additional capital contribution to the entity. No definition available. 
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- Definition 
          Proceeds From Issuance Of Common Stock Net Of Offering Cost No definition available. 
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- Definition 
          Amount of cash inflow (outflow) from operating activities, excluding discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          The cumulative amount of the reporting entity's undistributed earnings or deficit. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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