Annual report pursuant to Section 13 and 15(d)

CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS (Details 1)

v2.4.1.9
CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS (Details 1) (USD $)
12 Months Ended
Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
Dec. 31, 2011
Cash, cash equivalents and short term investments.        
Cash, cash equivalents and short-term investments $ 143,159,000us-gaap_CashCashEquivalentsAndShortTermInvestments $ 211,975,000us-gaap_CashCashEquivalentsAndShortTermInvestments    
Cash and cash equivalents 15,203,000us-gaap_CashAndCashEquivalentsAtCarryingValue 20,854,000us-gaap_CashAndCashEquivalentsAtCarryingValue 33,484,000us-gaap_CashAndCashEquivalentsAtCarryingValue 18,633,000us-gaap_CashAndCashEquivalentsAtCarryingValue
Short-term Investments 127,956,000us-gaap_ShortTermInvestments 191,121,000us-gaap_ShortTermInvestments    
Available-For-Sale Securities Reconciliation        
Amortized Cost 132,964,000us-gaap_AvailableForSaleSecuritiesAmortizedCost 202,674,000us-gaap_AvailableForSaleSecuritiesAmortizedCost    
Gross Unrealized Gains 25,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains 64,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains    
Gross Unrealized Losses (32,000)us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss (17,000)us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss    
Fair Value 132,957,000us-gaap_AvailableForSaleSecurities 202,721,000us-gaap_AvailableForSaleSecurities    
Years to Maturity        
Within one year 181,846,000us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount      
After One Year Through Two Years 20,875,000rigl_CashEquivalentsAndAvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoFairValue      
Weighted-average time to maturity of cash equivalents and available-for-sale securities 148 days      
Proceeds from sale of short term investments   16,479,000us-gaap_ProceedsFromSaleOfShortTermInvestments    
Number of investments in continuous unrealized loss position for more than twelve months 0us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear 4us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear    
Investments in unrealized loss position for more than twelve months   2,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss    
Fair value and gross unrealized losses of investments in individual securities in unrealized loss position        
Number of individual securities in unrealized loss position for twelve months or less 31us-gaap_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear      
Fair Value 57,563,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue      
Unrealized Losses (32,000)us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss      
Money Market Funds [Member]        
Cash, cash equivalents and short term investments.        
Cash, cash equivalents and short-term investments 10,027,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= us-gaap_MoneyMarketFundsMember
9,059,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= us-gaap_MoneyMarketFundsMember
   
U S Treasury Securities [Member]        
Cash, cash equivalents and short term investments.        
Cash, cash equivalents and short-term investments 2,010,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
2,085,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
   
Available-For-Sale Securities Reconciliation        
Amortized Cost 2,010,000us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
2,083,000us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
   
Gross Unrealized Gains   2,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
   
Fair Value 2,010,000us-gaap_AvailableForSaleSecurities
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
2,085,000us-gaap_AvailableForSaleSecurities
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
   
Years to Maturity        
After One Year Through Two Years 2,085,000rigl_CashEquivalentsAndAvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoFairValue
/ us-gaap_InvestmentTypeAxis
= us-gaap_USTreasurySecuritiesMember
     
U S Government Sponsored Enterprises Debt Securities [Member]        
Cash, cash equivalents and short term investments.        
Cash, cash equivalents and short-term investments 45,786,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
67,178,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
   
Available-For-Sale Securities Reconciliation        
Amortized Cost 45,793,000us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
67,160,000us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
   
Gross Unrealized Gains 4,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
29,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
   
Gross Unrealized Losses (11,000)us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
(11,000)us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
   
Fair Value 45,786,000us-gaap_AvailableForSaleSecurities
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
67,178,000us-gaap_AvailableForSaleSecurities
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
   
Years to Maturity        
Within one year 49,394,000us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
     
After One Year Through Two Years 17,784,000rigl_CashEquivalentsAndAvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoFairValue
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
     
Fair value and gross unrealized losses of investments in individual securities in unrealized loss position        
Fair Value 23,122,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
     
Unrealized Losses (11,000)us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_InvestmentTypeAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
     
Corporate Bond Securities And Commercial Paper [Member]        
Cash, cash equivalents and short term investments.        
Cash, cash equivalents and short-term investments 85,161,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
133,458,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
   
Available-For-Sale Securities Reconciliation        
Amortized Cost 85,161,000us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
133,431,000us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
   
Gross Unrealized Gains 21,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
33,000us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
   
Gross Unrealized Losses (21,000)us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
(6,000)us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
   
Fair Value 85,161,000us-gaap_AvailableForSaleSecurities
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
133,458,000us-gaap_AvailableForSaleSecurities
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
   
Years to Maturity        
Within one year 132,452,000us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
     
After One Year Through Two Years 1,006,000rigl_CashEquivalentsAndAvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoFairValue
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
     
Fair value and gross unrealized losses of investments in individual securities in unrealized loss position        
Fair Value 34,441,000us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
     
Unrealized Losses (21,000)us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_InvestmentTypeAxis
= rigl_CorporateBondSecuritiesAndCommercialPaperMember
     
Demand Deposits [Member]        
Cash, cash equivalents and short term investments.        
Cash, cash equivalents and short-term investments $ 175,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_CashAndCashEquivalentsAxis
= us-gaap_DemandDepositsMember
$ 195,000us-gaap_CashCashEquivalentsAndShortTermInvestments
/ us-gaap_CashAndCashEquivalentsAxis
= us-gaap_DemandDepositsMember