Income Taxes	9 Months Ended
Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company recorded a provision for (benefit from) income taxes of $(167.0) million and $5.3 million for the three months ended September 30, 2015 and 2014, respectively, and $(155.7) million and $17.2 million for the nine months ended September 30, 2015 and 2014, respectively. The benefit from income taxes for the three and nine months ended September 30, 2015 is primarily comprised of the tax benefit from the release of the valuation allowance on the Company's U.S. federal and state deferred tax assets, offset by federal, state and foreign taxes. The provision for income taxes for the three and nine months ended September 30, 2014 was primarily comprised of withholding taxes, state taxes and other foreign taxes based upon income earned during the period. During the three and nine months ended September 30, 2015, the Company paid withholding taxes of $5.4 million and $15.0 million. During the three and nine months ended September 30, 2014, the Company paid withholding taxes of $4.8 million and $14.6 million, respectively. As of September 30, 2015, the Company’s unaudited condensed consolidated balance sheets included net deferred tax assets, before valuation allowance, of approximately $182.7 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 notes. Management periodically evaluates the realizability of the Company's net deferred tax assets based on all available evidence, both positive and negative. The realizability of the Company's net deferred tax assets is dependent on its ability to generate sufficient future taxable income during periods prior to the expiration of tax attributes to fully utilize these assets. Management evaluated the realizability of its net deferred tax assets based on all available evidence, both positive and negative, in determining that it was appropriate to release the valuation allowance for the Company's U.S. federal income deferred tax assets of $174.4 million as of September 30, 2015 in accordance with FASB ASC 740-10-30-16 to 25. The Company emerged from a cumulative loss position over the previous three years during the first quarter of 2015. The cumulative three-year pre-tax income is considered positive evidence which is objective and verifiable, and thus, received significant weighting. The continued stability in the Company's operations along with the increased visibility into the adoption of its security technology in the third quarter of 2015 provided additional evidence to the Company’s belief that it will generate sufficient taxable income in the future. Additional positive evidence considered by management in its assessment included a lack of unused operating loss carryforwards in the Company's history as well as anticipated future benefits from the cost management by the Company. Negative evidence management considered included economic uncertainties such as volatility of the semiconductor industry and uncertainties associated with the development of new products that could impact the Company’s ability to generate a sustained level of future profits. Upon considering the relative impact of all evidence during the third quarter of 2015, both negative and positive, and the weight accorded to each, the Company concluded that it was more likely than not that its deferred tax assets would be realizable with the exception of primarily its California deferred tax assets that have not met the “more likely than not” realization threshold criteria. As a result, the Company released the related valuation allowance against such deferred tax assets which is included as a component of the benefit from income taxes in the accompanying unaudited condensed consolidated statement of operations. The Company continues to maintain a deferred tax asset valuation allowance of $20.9 million as of September 30, 2015. The Company maintains liabilities for uncertain tax positions within its long-term income taxes payable accounts and as a reduction to existing deferred tax assets to the extent tax attributes are available to offset such liabilities. 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 September 30, 2015, the Company had approximately $20.7 million of unrecognized tax benefits, including $18.5 million recorded as a reduction of long-term deferred tax assets and $2.2 million in long-term income taxes payable. If recognized, approximately $2.2 million would be recorded as an income tax benefit. Approximately $18.5 million would be recognized for the remaining unrecognized tax benefits recorded as a reduction of long-term deferred tax asset. As of December 31, 2014, the Company had $19.9 million of unrecognized tax benefits, including $17.8 million recorded as a reduction of long-term deferred tax assets and $2.1 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 September 30, 2015 and December 31, 2014, an immaterial amount of interest and penalties is included in long-term income taxes payable. Rambus files income tax returns for the U.S., California, India and various other state and foreign jurisdictions. The U.S. federal returns are subject to examination from 2012 and forward. The California returns are subject to examination from 2009 and forward. 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. The India returns are subject to examination from fiscal year ended March 2009 and forward. The Company is currently under examination by California for the 2010 and 2011 tax years. The Company’s India subsidiary is under examination by the Indian tax administration for tax years beginning 2009. These examinations may result in proposed adjustments to the income taxes as filed during these periods. Management regularly assesses the likelihood of outcomes resulting from income tax examinations to determine the adequacy of their provision for income taxes and believes their provision for unrecognized tax benefits is adequate. 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

The Company recorded a provision for (benefit from) income taxes of $(167.0) million and $5.3 million for the three months ended September 30, 2015 and 2014, respectively, and $(155.7) million and $17.2 million for the nine months ended September 30, 2015 and 2014, respectively. The benefit from income taxes for the three and nine months ended September 30, 2015 is primarily comprised of the tax benefit from the release of the valuation allowance on the Company's U.S. federal and state deferred tax assets, offset by federal, state and foreign taxes. The provision for income taxes for the three and nine months ended September 30, 2014 was primarily comprised of withholding taxes, state taxes and other foreign taxes based upon income earned during the period.

During the three and nine months ended September 30, 2015, the Company paid withholding taxes of $5.4 million and $15.0 million. During the three and nine months ended September 30, 2014, the Company paid withholding taxes of $4.8 million and $14.6 million, respectively.

As of September 30, 2015, the Company’s unaudited condensed consolidated balance sheets included net deferred tax assets, before valuation allowance, of approximately $182.7 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 notes.

Management periodically evaluates the realizability of the Company's net deferred tax assets based on all available evidence, both positive and negative. The realizability of the Company's net deferred tax assets is dependent on its ability to generate sufficient future taxable income during periods prior to the expiration of tax attributes to fully utilize these assets. Management evaluated the realizability of its net deferred tax assets based on all available evidence, both positive and negative, in determining that it was appropriate to release the valuation allowance for the Company's U.S. federal income deferred tax assets of $174.4 million as of September 30, 2015 in accordance with FASB ASC 740-10-30-16 to 25.

The Company emerged from a cumulative loss position over the previous three years during the first quarter of 2015. The cumulative three-year pre-tax income is considered positive evidence which is objective and verifiable, and thus, received significant weighting. The continued stability in the Company's operations along with the increased visibility into the adoption of its security technology in the third quarter of 2015 provided additional evidence to the Company’s belief that it will generate sufficient taxable income in the future. Additional positive evidence considered by management in its assessment included a lack of unused operating loss carryforwards in the Company's history as well as anticipated future benefits from the cost management by the Company. Negative evidence management considered included economic uncertainties such as volatility of the semiconductor industry and uncertainties associated with the development of new products that could impact the Company’s ability to generate a sustained level of future profits.

Upon considering the relative impact of all evidence during the third quarter of 2015, both negative and positive, and the weight accorded to each, the Company concluded that it was more likely than not that its deferred tax assets would be realizable with the exception of primarily its California deferred tax assets that have not met the “more likely than not” realization threshold criteria. As a result, the Company released the related valuation allowance against such deferred tax assets which is included as a component of the benefit from income taxes in the accompanying unaudited condensed consolidated statement of operations. The Company continues to maintain a deferred tax asset valuation allowance of $20.9 million as of September 30, 2015.

The Company maintains liabilities for uncertain tax positions within its long-term income taxes payable accounts and as a reduction to existing deferred tax assets to the extent tax attributes are available to offset such liabilities. 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 September 30, 2015, the Company had approximately $20.7 million of unrecognized tax benefits, including $18.5 million recorded as a reduction of long-term deferred tax assets and $2.2 million in long-term income taxes payable. If recognized, approximately $2.2 million would be recorded as an income tax benefit. Approximately $18.5 million would be recognized for the remaining unrecognized tax benefits recorded as a reduction of long-term deferred tax asset. As of December 31, 2014, the Company had $19.9 million of unrecognized tax benefits, including $17.8 million recorded as a reduction of long-term deferred tax assets and $2.1 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 September 30, 2015 and December 31, 2014, an immaterial amount of interest and penalties is included in long-term income taxes payable.

Rambus files income tax returns for the U.S., California, India and various other state and foreign jurisdictions. The U.S. federal returns are subject to examination from 2012 and forward. The California returns are subject to examination from 2009 and forward. 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. The India returns are subject to examination from fiscal year ended March 2009 and forward. The Company is currently under examination by California for the 2010 and 2011 tax years. The Company’s India subsidiary is under examination by the Indian tax administration for tax years beginning 2009. These examinations may result in proposed adjustments to the income taxes as filed during these periods. Management regularly assesses the likelihood of outcomes resulting from income tax examinations to determine the adequacy of their provision for income taxes and believes their provision for unrecognized tax benefits is adequate.

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.