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

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.

+ Details

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

- Details

Name:	rmbs_BusinessAcquisitionAbstract
Namespace Prefix:	rmbs
Data Type:	xbrli:stringItemType
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.

+ 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.

+ Details

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

- Definition

The cash outflow to reacquire contingently redeemable common stock during the period.

+ Details

Name:	rmbs_PaymentToRedeemContingentlyRedeemableCommonStock
Namespace Prefix:	rmbs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the period for which Samsung is not allowed to transfer shares.

+ Details

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

- Definition

Represents original issue price per share under purchase agreement.

+ 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).

+ 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).

+ 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

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Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of new stock issued during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

-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.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

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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

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Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Stockholders' Equity and Contingently Redeemable Common Stock (Details) (USD $)	1 Months Ended			9 Months Ended
	Aug. 31, 2011	Jun. 30, 2011	Jan. 31, 2010	Sep. 30, 2011	Jul. 20, 2011	Dec. 31, 2010	Jan. 19, 2010
Contingently Redeemable Common Stock
Issuance of common stock (in shares)			9,600,000
Beginning period for validity of sell back right due to the settlement agreement with Samsung (in months)							$ 18
Ending period for validity of sell back right due to the settlement agreement with Samsung (in months)							$ 19
Maximum number of shares sell back due to the settlement agreement with Samsung (in shares)							4,800,000
Original issue price per share due to the settlement agreement with Samsung (in dollars per share)							$ 20.885
Contingently redeemable common stock, shares issued (in shares)				0		4,788,125
Actual number of shares put back due to the settlement agreement with Samsung within 30 days (in shares)					4,800,000
Actual value of shares put back within 30 days					$ 100,000,000
Amount paid for actual value of shares put back	100,000,000			100,000,000
Business Acquisition
Purchase price paid (in shares)		6,380,806
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 validity of sell back right due to the settlement agreement with Samsung (in months)							$ 19
Maximum number of shares sell back due to the settlement agreement with Samsung (in shares)							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							100,000,000
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 (in shares)					4,800,000
Actual value of shares put back within 30 days					100,000,000
Amount paid for actual value of shares put back	$ 100,000,000
CRI
Business Acquisition
Purchase price paid (in shares)		6,400,000
Shares withheld by the entity (in shares)		161,000