Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Summary of Cash, Cash Equivalents and Marketable Securities (Detail)

v2.4.1.9
Fair Value Measurements - Summary of Cash, Cash Equivalents and Marketable Securities (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Mar. 31, 2014
Dec. 31, 2013
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Cash, amortized cost and estimated fair value $ 11,225us-gaap_Cash      
Cash and cash equivalents, amortized cost and estimated fair value 25,278us-gaap_CashAndCashEquivalentsAtCarryingValue 27,897us-gaap_CashAndCashEquivalentsAtCarryingValue 28,630us-gaap_CashAndCashEquivalentsAtCarryingValue 14,593us-gaap_CashAndCashEquivalentsAtCarryingValue
Restricted cash, amortized cost and estimated fair value 190us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue 251us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue    
Amortized Cost 15,096us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis      
Gross Unrealized Gains 2us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax      
Gross Unrealized Losses (7)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax      
Estimated Fair Value 15,091us-gaap_AvailableForSaleSecuritiesDebtSecurities      
Money market securities [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Cash equivalents, amortized cost and estimated fair value 14,053us-gaap_CashEquivalentsAtCarryingValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MoneyMarketFundsMember
     
Restricted cash, amortized cost and estimated fair value 190us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue
/ us-gaap_FairValueByAssetClassAxis
= us-gaap_MoneyMarketFundsMember
     
Corporate bonds and commercial paper [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Amortized Cost 15,096us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
/ us-gaap_FairValueByAssetClassAxis
= ogxi_CorporateBondsAndCommercialPaperShortTermMember
     
Gross Unrealized Gains 2us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
/ us-gaap_FairValueByAssetClassAxis
= ogxi_CorporateBondsAndCommercialPaperShortTermMember
     
Gross Unrealized Losses (7)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
/ us-gaap_FairValueByAssetClassAxis
= ogxi_CorporateBondsAndCommercialPaperShortTermMember
     
Estimated Fair Value $ 15,091us-gaap_AvailableForSaleSecuritiesDebtSecurities
/ us-gaap_FairValueByAssetClassAxis
= ogxi_CorporateBondsAndCommercialPaperShortTermMember