Name:	rmbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodIncreaseInAvailableForGrant
Namespace Prefix:	rmbs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

For purposes of determining the number of shares available for grant under the Equity Incentive Plan, represents the multiplier by which the number of shares available for grant will increase, for every restricted stock award forfeited.

No definition available.

Name:	rmbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodIncreaseInAvailableForGrantForEveryForfeiture
Namespace Prefix:	rmbs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Represents the decrease in number of shares available for grant under the stock incentive plans, which is based on a factor of 1.5 for every restricted stock award granted for the period.

No definition available.

Name:	rmbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodDecreaseInAvailableForGrant
Namespace Prefix:	rmbs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

For purposes of determining the number of shares available for grant under the Equity Incentive Plan, represents the multiplier by which the number of shares available for grant will decrease, for every restricted stock award granted.

No definition available.

Name:	rmbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodDecreaseInAvailableForGrantForEveryGrant
Namespace Prefix:	rmbs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

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

No definition available.

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

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_AwardTypeAxis=us-gaap_StockCompensationPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AwardDateAxis=rmbs_AwardDatePeriod1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AwardDateAxis=rmbs_AwardDatePeriod2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: