Income Taxes	3 Months Ended
Mar. 31, 2013
Income Tax Expense (Benefit) [Abstract]
Income Taxes	Income Taxes During the three months ended March 31, 2013, the Company calculated its interim tax provision to record taxes incurred by the U.S. entity on a discrete basis because the Company is projecting losses in which a tax benefit cannot be recognized in accordance with FASB Accounting Standards Codification (“ASC”) 740, Income Taxes. The Company recorded a provision for income taxes of $4.5 million and $3.9 million for the three months ended March 31, 2013 and 2012, respectively. The provision for income taxes for the three months ended March 31, 2013 and 2012, is primarily comprised of withholding taxes and other foreign taxes based upon income earned during the period with no tax benefit recorded for the loss jurisdictions. During the three months ended March 31, 2013 and 2012, the Company paid withholding taxes of $3.8 million and $4.4 million, respectively. As of March 31, 2013, the Company’s condensed consolidated balance sheets included net deferred tax assets, before valuation allowance, of approximately $211.0 million, which consists of net operating loss carryovers, tax credit carryovers, amortization, employee stock-based compensation expenses and certain liabilities, partially reduced by deferred tax liabilities associated with the convertible debt instruments. As of March 31, 2013, a full valuation allowance has been recorded against the U.S. deferred tax assets. During the three months ended March 31, 2013, the Company did not significantly change its deferred tax assets. Management periodically evaluates the realizability of the Company's net deferred tax assets based on all available evidence, both positive and negative. The realization of net deferred tax assets is dependent on the Company's ability to generate sufficient future taxable income during periods prior to the expiration of tax statutes to fully utilize these assets. The Company's forecasted future operating results are highly influenced by, among other factors, assumptions regarding the Company's (1) ability to achieve its forecasted revenue, (2) ability to effectively manage its expenses in line with its forecasted revenue and (3) general trends in the industries in which it operates. The Company maintains liabilities for uncertain tax positions within its long-term income taxes payable accounts. These liabilities involve judgment and estimation and are monitored by management based on the best information available including changes in tax regulations, the outcome of relevant court cases and other information. As of March 31, 2013, the Company had approximately $16.8 million of unrecognized tax benefits, including $10.6 million recorded as a reduction of long-term deferred tax assets and $6.2 million in long-term income taxes payable. If recognized, approximately $2.0 million would be recorded as an income tax benefit. No benefit would be recorded for the remaining unrecognized tax benefits as the recognition would require a corresponding increase in the valuation allowance. As of December 31, 2012, the Company had $16.8 million of unrecognized tax benefits, including $10.6 million recorded as a reduction of long-term deferred tax assets and $6.2 million recorded in long-term income taxes payable. Although it is possible that some of the unrecognized tax benefits could be settled within the next 12 months, the Company cannot reasonably estimate the outcome at this time. The Company recognizes interest and penalties related to uncertain tax positions as a component of the income tax provision. At March 31, 2013 and December 31, 2012, an immaterial amount of interest and penalties are included in long-term income taxes payable. On January 2, 2013, the President signed into law The American Taxpayer Relief Act of 2012, or ATRA. Under prior law, a taxpayer was entitled to a research tax credit for qualifying amounts incurred through December 31, 2011. The ATRA extends the research credit for two years for qualified research expenditures incurred through the end of 2013. The extension of the research credit is retroactive and includes amounts incurred after 2011. There was no benefit to the Company of the restated research credit in the first quarter of 2013 due to the full valuation allowance. Rambus files U.S. federal income tax returns as well as income tax returns in various states and foreign jurisdictions. The Company is no longer subject to examination by the Internal Revenue Service (“IRS”) for tax years before 2009. The Company is no longer subject to examination by the State of California for tax years before 2008. In addition, any research and development credit carryforward or net operating loss carryforward generated in prior years and utilized in these or future years may also be subject to examination by the IRS and the State of California. The IRS commenced an exam of the Company's 2010 through 2011 tax years during the first quarter of 2013. The Company is also subject to examination in various other foreign jurisdictions, including India, for various periods. Additionally, the Company's future effective tax rates could be adversely affected by earnings being higher than anticipated in countries where the Company has higher statutory rates or lower than anticipated in countries where it has lower statutory rates, by changes in valuation of its deferred tax assets and liabilities or by changes in tax laws or interpretations of those laws.

Income Taxes

During the three months ended March 31, 2013, the Company calculated its interim tax provision to record taxes incurred by the U.S. entity on a discrete basis because the Company is projecting losses in which a tax benefit cannot be recognized in accordance with FASB Accounting Standards Codification (“ASC”) 740, Income Taxes. The Company recorded a provision for income taxes of $4.5 million and $3.9 million for the three months ended March 31, 2013 and 2012, respectively. The provision for income taxes for the three months ended March 31, 2013 and 2012, is primarily comprised of withholding taxes and other foreign taxes based upon income earned during the period with no tax benefit recorded for the loss jurisdictions.

During the three months ended March 31, 2013 and 2012, the Company paid withholding taxes of $3.8 million and $4.4 million, respectively.

As of March 31, 2013, the Company’s condensed consolidated balance sheets included net deferred tax assets, before valuation allowance, of approximately $211.0 million, which consists of net operating loss carryovers, tax credit carryovers, amortization, employee stock-based compensation expenses and certain liabilities, partially reduced by deferred tax liabilities associated with the convertible debt instruments. As of March 31, 2013, a full valuation allowance has been recorded against the U.S. deferred tax assets. During the three months ended March 31, 2013, the Company did not significantly change its deferred tax assets.

Management periodically evaluates the realizability of the Company's net deferred tax assets based on all available evidence, both positive and negative. The realization of net deferred tax assets is dependent on the Company's ability to generate sufficient future taxable income during periods prior to the expiration of tax statutes to fully utilize these assets. The Company's forecasted future operating results are highly influenced by, among other factors, assumptions regarding the Company's (1) ability to achieve its forecasted revenue, (2) ability to effectively manage its expenses in line with its forecasted revenue and (3) general trends in the industries in which it operates.

The Company maintains liabilities for uncertain tax positions within its long-term income taxes payable accounts. These liabilities involve judgment and estimation and are monitored by management based on the best information available including changes in tax regulations, the outcome of relevant court cases and other information.

As of March 31, 2013, the Company had approximately $16.8 million of unrecognized tax benefits, including $10.6 million recorded as a reduction of long-term deferred tax assets and $6.2 million in long-term income taxes payable. If recognized, approximately $2.0 million would be recorded as an income tax benefit. No benefit would be recorded for the remaining unrecognized tax benefits as the recognition would require a corresponding increase in the valuation allowance. As of December 31, 2012, the Company had $16.8 million of unrecognized tax benefits, including $10.6 million recorded as a reduction of long-term deferred tax assets and $6.2 million recorded in long-term income taxes payable.

Although it is possible that some of the unrecognized tax benefits could be settled within the next 12 months, the Company cannot reasonably estimate the outcome at this time.

The Company recognizes interest and penalties related to uncertain tax positions as a component of the income tax provision. At March 31, 2013 and December 31, 2012, an immaterial amount of interest and penalties are included in long-term income taxes payable.

On January 2, 2013, the President signed into law The American Taxpayer Relief Act of 2012, or ATRA. Under prior law, a taxpayer was entitled to a research tax credit for qualifying amounts incurred through December 31, 2011. The ATRA extends the research credit for two years for qualified research expenditures incurred through the end of 2013. The extension of the research credit is retroactive and includes amounts incurred after 2011. There was no benefit to the Company of the restated research credit in the first quarter of 2013 due to the full valuation allowance.

Rambus files U.S. federal income tax returns as well as income tax returns in various states and foreign jurisdictions. The Company is no longer subject to examination by the Internal Revenue Service (“IRS”) for tax years before 2009. The Company is no longer subject to examination by the State of California for tax years before 2008. In addition, any research and development credit carryforward or net operating loss carryforward generated in prior years and utilized in these or future years may also be subject to examination by the IRS and the State of California. The IRS commenced an exam of the Company's 2010 through 2011 tax years during the first quarter of 2013. The Company is also subject to examination in various other foreign jurisdictions, including India, for various periods.

Additionally, the Company's future effective tax rates could be adversely affected by earnings being higher than anticipated in countries where the Company has higher statutory rates or lower than anticipated in countries where it has lower statutory rates, by changes in valuation of its deferred tax assets and liabilities or by changes in tax laws or interpretations of those laws.