XML 84 R60.htm IDEA: XBRL DOCUMENT v2.4.1.9
Marketable Securities (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Cash equivalents and marketable securities    
Fair Value $ 270,921us-gaap_AvailableForSaleSecurities $ 359,097us-gaap_AvailableForSaleSecurities
Amortized Cost 271,034us-gaap_AvailableForSaleSecuritiesAmortizedCost 359,112us-gaap_AvailableForSaleSecuritiesAmortizedCost
Cash Cash Equivalents And Short Term Investments Unrealized Gains 1rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedGains 0rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedGains
CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses 114rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses 15rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses
Gross Unrealized Gains 1rmbs_GrossUnrealizedGainOnSecuritiesAndCash 0rmbs_GrossUnrealizedGainOnSecuritiesAndCash
Gross Unrealized Losses 114rmbs_GrossUnrealizedLossOnSecuritiesAndCash 15rmbs_GrossUnrealizedLossOnSecuritiesAndCash
Cash, fair value 29,188rmbs_CashFairValueDisclosure 28,565rmbs_CashFairValueDisclosure
Cash 29,188us-gaap_Cash 28,565us-gaap_Cash
Cash, cash equivalents and marketable securities    
Fair Value 300,109rmbs_CashCashEquivalentsAndShortTermInvestmentsFairValueDisclosure 387,662rmbs_CashCashEquivalentsAndShortTermInvestmentsFairValueDisclosure
Amortized Cost 300,222rmbs_CashCashEquivalentsAndShortTermInvestmentsAmortizedCostDisclosure 387,677rmbs_CashCashEquivalentsAndShortTermInvestmentsAmortizedCostDisclosure
Money market funds    
Cash equivalents and marketable securities    
Fair Value 124,938us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
300,605us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
Amortized Cost 124,938us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
300,605us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
Cash Cash Equivalents And Short Term Investments Unrealized Gains 0rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedGains
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
0rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedGains
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses 0rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
0rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
Weighted Rate of Return (as a percent) 0.01%rmbs_AvailableForSaleSecuritiesWeightedRateOfReturn
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
0.01%rmbs_AvailableForSaleSecuritiesWeightedRateOfReturn
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MoneyMarketFundsMember
Corporate notes, bonds and commercial paper    
Cash equivalents and marketable securities    
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value 139,989us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
53,491us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Maximum maturity period of available-for-sale securities (in years) 3 years  
Maximum remaining maturity period of available-for-sale securities (in years) 1 year  
Fair Value 145,983us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
58,492us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Amortized Cost 146,096us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
58,507us-gaap_AvailableForSaleSecuritiesAmortizedCost
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Cash Cash Equivalents And Short Term Investments Unrealized Gains 1rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedGains
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
0rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedGains
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses 114rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
15rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Weighted Rate of Return (as a percent) 0.25%rmbs_AvailableForSaleSecuritiesWeightedRateOfReturn
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
0.15%rmbs_AvailableForSaleSecuritiesWeightedRateOfReturn
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Unrealized gain (loss), net    
Less than one year, Gross unrealized loss (114)us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
(15)us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Cash equivalents    
Cash equivalents and marketable securities    
Maximum remaining maturity period of available-for-sale securities (in years) 1 year  
Fair Value 124,938us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CashEquivalentsMember
310,131us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CashEquivalentsMember
Short term marketable securities    
Cash equivalents and marketable securities    
Fair Value $ 145,983us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_ShortTermInvestmentsMember
$ 48,966us-gaap_AvailableForSaleSecurities
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_ShortTermInvestmentsMember