Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity - Company's Outstanding and Exercisable Warrants (Detail)

v2.4.1.9
Shareholders' Equity - Company's Outstanding and Exercisable Warrants (Detail) (USD $)
 12 Months Ended
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Warrants issued / Retained warrants 2,532,094us-gaap_ClassOfWarrantOrRightOutstanding
Class of Warrant One [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Warrants exercisable price per share $ 1.50us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_ClassOfWarrantOrRightAxis
= ogen_ClassOfWarrantOneMember
Warrants issued / Retained warrants 361,169us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= ogen_ClassOfWarrantOneMember
Expiration Dates Jul. 31, 2017
Class of Warrant Two [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Warrants exercisable price per share $ 2.00us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
/ us-gaap_ClassOfWarrantOrRightAxis
= ogen_ClassOfWarrantTwoMember
Warrants issued / Retained warrants 2,170,925us-gaap_ClassOfWarrantOrRightOutstanding
/ us-gaap_ClassOfWarrantOrRightAxis
= ogen_ClassOfWarrantTwoMember
Expiration Dates Mar. 23, 2015