Represents the actual number of shares put back to the entity under the stock purchase agreement within 30 days.

No definition available.

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

- Definition

Represents the actual value for the shares under the put back facility of the stock purchase agreement within 30 days.

+ References

No definition available.

+ Details

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

- Definition

Total Number of new stocks including Common Stocks and Contingently Redeemable Common Stocks issued during the period due to Samsung Settlement.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Represents the number of shares acquired in a business combination which are used to satisfy the tax withholding obligations.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Represents the maximum number of shares that can be put back to the entity under the stock purchase agreement.

+ References

No definition available.

+ Details

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

- Definition

Represents the maximum value for the shares under the put back facility of the stock purchase agreement.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of contingently redeemable common stock shares that were retired.

+ References

No definition available.

+ Details

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

- Definition

Represents the period after the date of the Stock Purchase Agreement for which Samsung is not allowed to transfer shares.

+ References

No definition available.

+ Details

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

- Definition

Represents the period after the date of the Stock Purchase Agreement for which Samsung is not allowed to transfer shares

+ References

No definition available.

+ Details

Name:	rmbs_ProhibitedPeriodForSharesTransfer
Namespace Prefix:	rmbs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Represents original issue price per share under purchase agreement.

+ References

No definition available.

+ Details

Name:	rmbs_StockPricePerShareUnderPurchaseAgreement
Namespace Prefix:	rmbs_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the period after the date of stock purchase agreement, by which Samsung can exercise its put right (in months).

+ References

No definition available.

+ Details

Name:	rmbs_ValidityOfPutBackRightEndPeriod
Namespace Prefix:	rmbs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the period after the date of stock purchase agreement, from which Samsung can exercise its put right (in months).

+ References

No definition available.

+ Details

Name:	rmbs_ValidityOfPutBackRightStartPeriod
Namespace Prefix:	rmbs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

The number of securities classified as temporary equity that have been sold (or granted) to the entity's shareholders. Securities issued include securities outstanding and securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 02

-Paragraph 28

-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.27(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

Stockholders' Equity and Contingently Redeemable Common Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended		3 Months Ended	12 Months Ended
	Aug. 31, 2011	Jun. 30, 2011	Mar. 31, 2010	Dec. 31, 2011	Jul. 20, 2011	Dec. 31, 2010	Jan. 19, 2010 M
Settlement agreement
Stock Issued During Period, Shares, New Issues			9,600,000
Business Acquisition
Purchase price paid (in shares)		6,380,806
Number of shares used to satisfy tax withholding obligations				161,000
Contingently Redeemable Common Stock
Beginning period for validity of sell back right due to the settlement agreement with Samsung (in months)							18
Ending period for validityto put back right due to the settlement agreement with Samsung (in months)							19
Contingently redeemable common stock, shares issued (in shares)				0		4,788,125
Prohibited period for transfer of shares by Samsung (in months)							18
Actual number of shares put back due to the settlement agreement with Samsung within 30 days					4,800,000
Actual value of shares put back within 30 days					$ 100.0
Amount paid for actual value of shares put back	100.0
Number of retired contingently redeemable common stocks	4,800,000
CRI
Business Acquisition
Purchase price paid (in shares)		6,400,000
Number of shares used to satisfy tax withholding obligations		161,000
CRCS
Contingently Redeemable Common Stock
Beginning period for validity of sell back right due to the settlement agreement with Samsung (in months)							18
Ending period for validityto put back right due to the settlement agreement with Samsung (in months)							19
Maximum number of shares put back due to the settlement agreement with Samsung							4,800,000
Original issue price per share due to the settlement agreement with Samsung (in dollars per share)							20.885
Maximum aggregate purchase price due to the settlement agreement with Samsung							100.0
Contingently redeemable common stock, shares issued (in shares)						4,800,000
Prohibited period for transfer of shares by Samsung (in months)							18
Actual number of shares put back due to the settlement agreement with Samsung within 30 days					4,800,000
Actual value of shares put back within 30 days					$ 100.0