Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Additional Information (Detail)

v2.4.1.9
Common Stock - Additional Information (Detail) (Non- employee Directors [Member], 2012 Equity Incentive Plan [Member], Restricted Stock [Member], USD $)
0 Months Ended 3 Months Ended
Mar. 16, 2015
Mar. 31, 2015
Non- employee Directors [Member] | 2012 Equity Incentive Plan [Member] | Restricted Stock [Member]
   
Class of Stock [Line Items]    
Restricted shares awarded 40,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_PlanNameAxis
= ogen_TwoThousandTwelveEquityIncentivePlanMember
/ us-gaap_TitleOfIndividualAxis
= ogen_NonEmployeeDirectorsMember
 
Restricted shares vest in each quarter end   10,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_PlanNameAxis
= ogen_TwoThousandTwelveEquityIncentivePlanMember
/ us-gaap_TitleOfIndividualAxis
= ogen_NonEmployeeDirectorsMember
Unrecognized compensation expense   $ 198,000ogen_UnrecognizedCompensationExpense
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
/ us-gaap_PlanNameAxis
= ogen_TwoThousandTwelveEquityIncentivePlanMember
/ us-gaap_TitleOfIndividualAxis
= ogen_NonEmployeeDirectorsMember