Name:	rmbs_AvailableForSaleSecuritiesWeightedRateOfReturn
Namespace Prefix:	rmbs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

This item represents the amortized cost of cash, cash equivalents and marketable securities, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

No definition available.

Name:	rmbs_CashCashEquivalentsAndShortTermInvestmentsAmortizedCostDisclosure
Namespace Prefix:	rmbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This element represents the aggregate of cash, cash equivalents and marketable securities reported on the balance sheet at period end measured at fair value by the entity.

No definition available.

Name:	rmbs_CashCashEquivalentsAndShortTermInvestmentsFairValueDisclosure
Namespace Prefix:	rmbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Cash Cash Equivalents And Short Term Investments Unrealized Gains

No definition available.

Name:	rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedGains
Namespace Prefix:	rmbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Cash Cash Equivalents And Short Term Investments Unrealized Losses

No definition available.

Name:	rmbs_CashCashEquivalentsAndShortTermInvestmentsUnrealizedLosses
Namespace Prefix:	rmbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty.

No definition available.

Name:	rmbs_CashFairValueDisclosure
Namespace Prefix:	rmbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This item represents the gross unrealized gains for cash, cash equivalents and marketable securities

No definition available.

Name:	rmbs_GrossUnrealizedGainOnSecuritiesAndCash
Namespace Prefix:	rmbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This item represents the gross unrealized losses for cash, cash equivalents and marketable securities.

No definition available.

Name:	rmbs_GrossUnrealizedLossOnSecuritiesAndCash
Namespace Prefix:	rmbs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the maximum maturity period of securities invested by the entity.

No definition available.

Name:	rmbs_MaximumMaturityPeriodAvailableForSaleSecurities
Namespace Prefix:	rmbs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the maximum remaining maturity period of securities invested by the entity.

No definition available.

Name:	rmbs_MaximumRemainingMaturityPeriodAvailableForSaleSecurities
Namespace Prefix:	rmbs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

-- None. No documentation exists for this element. --

No definition available.

Name:	rmbs_ScheduleOfAvailableForSaleSecuritiesAndCashLineItems
Namespace Prefix:	rmbs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

No definition available.

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months.

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_Cash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

Name:	us-gaap_CashCashEquivalentsAndShortTermInvestmentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentShorttermDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ShortTermInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: