Commitments and Contingencies - Schedule of Material Contractual Obligations (Parenthetical) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2026	Dec. 31, 2025
Contractual obligations
Unrecognized tax benefit excluding foreign tax withholdings	$ 26,700
Unrecognized tax benefits	26,400	$ 108,000
Long-term deferred tax assets	$ 86,500	105,542
Software licenses
Contractual obligations
Terms of noncancellable license agreements, minimum (in years)	1 year
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent
Contractual obligations
Unrecognized tax benefits	$ 800	1,000
Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent \| Unrecognized tax benefits, including interest
Contractual obligations
Unrecognized tax benefits	1,100
Location, Statement of Financial Position, Balance [Axis]: rmbs:DeferredTaxAssetsLongTerm
Contractual obligations
Unrecognized tax benefits	25,600	$ 24,300
Long-term deferred tax assets	$ 25,600