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

Represents the additional number of shares authorized to be repurchased by the entity's Board of Directors under the stock repurchase plan.

No definition available.

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

The cumulative number of shares that have been repurchased since the commencement of the stock repurchase agreement.

No definition available.

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

The cumulative value of shares that have been repurchased since the commencement of the stock repurchase agreement.

No definition available.

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

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

No definition available.

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

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

No definition available.

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

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stockholders' Equity (details 1) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 25, 2010	Jan. 21, 2015
Share repurchase program
Number of shares authorized to be repurchased under the plan	19,000,000
Additional number of shares authorized to be repurchased		12,500,000
Cumulative shares that have been repurchased in stock repurchase program	26,300,000
Cumulative value of shares that have been repurchased in stock repurchase program	$ 428.9
Remaining shares authorized to be repurchased	5,200,000
Subsequent Event [Member]
Share repurchase program
Number of shares authorized to be repurchased under the plan			20,000,000