Summary of Significant Accounting Policies (Details 5)	12 Months Ended
Dec. 31, 2020
Stock-Based Compensation and Equity Incentive Plans
Discount from the fair market value (as a percent)	15.00%

The discount rate from market value on specific date that participants pay for shares.

No definition available.

Name:	rmbs_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceSpecificDate
Namespace Prefix:	rmbs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration