v3.24.0.1

Significant Accounting Policies and Basis of Presentation - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Beginning balance | $ 40,191 |  |
Ending balance | 34,127 | $ 40,191 |
Allowance for doubtful accounts |  |  |
Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Beginning balance | 3,498 | 2,158 | $ 4,181
Provision for (recoveries of) doubtful accounts | 1,674 | 2,081 | (904)
Adjustments for write-off | (2,959) | (741) | (1,119)
Ending balance | $ 2,213 | $ 3,498 | $ 2,158

X
- Definition Valuation allowances and reserves adjustments for (recovery) and write-off. + References No definition available. + Details
Name: | roku_ValuationAllowancesAndReservesAdjustmentsForRecoveryAndWriteOff
Namespace Prefix: | roku_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_MovementInValuationAllowancesAndReservesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column B)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-4 + Details
Name: | us-gaap_ValuationAllowancesAndReservesBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column C)(1)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-4 + Details
Name: | us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForCreditLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |