| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | Roku, Inc. |
| Entity Central Index Key | 0001428439 |
| Pay vs Performance Disclosure - USD ($) | 12 Months Ended | ||
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | Pay Versus Performance Below we provide disclosure regarding executive compensation for our CEO and non-CEO ink co The amounts set forth below under the headings “Compensation Actually Paid to CEO” and “Average Compensation Actually Paid to Non-CEO Fiscal Year (1) Summary Compensation (2) Average Summary Non-CEO Average Non-CEO NEOs ($) (3) Value of Initial Fixed $100 Net Income TSR ($) Peer Group (4) 2022 20,991,685 (77,933,918 ) 20,448,128 5,762,267 30.40 101.45 (498,005 ) 2021 18,133,692 (51,681,097 ) 5,005,742 (7,130,167 ) 170.43 194.17 242,385 2020 15,363,568 222,680,143 4,194,073 41,724,637 247.96 138.87 (17,507 ) (1) The CEO in each year was Anthony Wood. The non-CEO non-CEO ephen H (2) To determine the CAP to our CEO, the amounts reported in the Total column of the Summary Compensation Table for the applicable year were adjusted as follows: 2022 ($) 2021 ($) 2020 ($) Summary Compensation Table Total for CEO 20,991,685 18,133,692 15,363,568 - Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year (19,775,041 ) (16,917,387 ) (14,122,763 ) + Fair Value at Fiscal Year-End 6,900,189 6,035,966 52,724,467 + Year over Year Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years (58,312,566 ) (69,472,019 ) 158,286,976 + Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year 2,732,858 — — + Year over Year Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year (30,471,043 ) 10,538,650 10,427,895 - Fair Value as of Prior Fiscal Year-End — — — Compensation Actually Paid to CEO (77,933,918 ) (51,681,097 ) 222,680,143 (3) To determine the average CAP to our non-CEO 2022 ($) 2021 ($) 2020 ($) Average Summary Compensation Table Total for Non-CEO 20,448,128 5,005,742 4,194,073 - Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year (18,676,467 ) (4,270,687 ) (3,456,374 ) + Fair Value at Fiscal Year-End 11,948,736 1,812,690 12,999,355 + Year over Year Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years (5,741,438 ) 11,647,173 25,810,598 + Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year 1,067,751 — — + Year over Year Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year (3,284,443 ) 1,969,261 2,176,985 - Fair Value as of Prior Fiscal Year-End — — — Average Compensation Actually Paid to Non-CEO 5,762,267 (7,130,167 ) 41,724,637 (4) Roku’s TSR and the Peer Group TSR reflected in these columns for each fiscal year is calculated based on a fixed investment on December 31, 2019 of $100 through the end of the applicable fiscal year on the same cumulative basis as is used in Item 201(e) of Regulation S-K. 10-K 10-K | ||
| Named Executive Officers, Footnote [Text Block] | The CEO in each year was Anthony Wood. The non-CEO non-CEO ephen H | ||
| Peer Group Issuers, Footnote [Text Block] | Roku’s TSR and the Peer Group TSR reflected in these columns for each fiscal year is calculated based on a fixed investment on December 31, 2019 of $100 through the end of the applicable fiscal year on the same cumulative basis as is used in Item 201(e) of Regulation S-K. 10-K 10-K | ||
| PEO Total Compensation Amount | $ 20,991,685 | $ 18,133,692 | $ 15,363,568 |
| PEO Actually Paid Compensation Amount | $ (77,933,918) | (51,681,097) | 222,680,143 |
| Adjustment To PEO Compensation, Footnote [Text Block] | (2) To determine the CAP to our CEO, the amounts reported in the Total column of the Summary Compensation Table for the applicable year were adjusted as follows: 2022 ($) 2021 ($) 2020 ($) Summary Compensation Table Total for CEO 20,991,685 18,133,692 15,363,568 - Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year (19,775,041 ) (16,917,387 ) (14,122,763 ) + Fair Value at Fiscal Year-End 6,900,189 6,035,966 52,724,467 + Year over Year Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years (58,312,566 ) (69,472,019 ) 158,286,976 + Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year 2,732,858 — — + Year over Year Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year (30,471,043 ) 10,538,650 10,427,895 - Fair Value as of Prior Fiscal Year-End — — — Compensation Actually Paid to CEO (77,933,918 ) (51,681,097 ) 222,680,143 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 20,448,128 | 5,005,742 | 4,194,073 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 5,762,267 | (7,130,167) | 41,724,637 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | (3) To determine the average CAP to our non-CEO 2022 ($) 2021 ($) 2020 ($) Average Summary Compensation Table Total for Non-CEO 20,448,128 5,005,742 4,194,073 - Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year (18,676,467 ) (4,270,687 ) (3,456,374 ) + Fair Value at Fiscal Year-End 11,948,736 1,812,690 12,999,355 + Year over Year Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years (5,741,438 ) 11,647,173 25,810,598 + Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year 1,067,751 — — + Year over Year Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year (3,284,443 ) 1,969,261 2,176,985 - Fair Value as of Prior Fiscal Year-End — — — Average Compensation Actually Paid to Non-CEO 5,762,267 (7,130,167 ) 41,724,637 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | |||
| Compensation Actually Paid vs. Net Income [Text Block] | |||
| Total Shareholder Return Vs Peer Group [Text Block] | |||
| Total Shareholder Return Amount | $ 30.4 | 170.43 | 247.96 |
| Peer Group Total Shareholder Return Amount | 101.45 | 194.17 | 138.87 |
| Net Income (Loss) | $ (498,005,000) | 242,385,000 | (17,507,000) |
| PEO Name | Anthony Wood | ||
| PEO [Member] | Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (19,775,041) | (16,917,387) | (14,122,763) |
| PEO [Member] | Fair Value at Fiscal YearEnd of Outstanding and Unvested Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 6,900,189 | 6,035,966 | 52,724,467 |
| PEO [Member] | Year over Year Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (58,312,566) | (69,472,019) | 158,286,976 |
| PEO [Member] | Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 2,732,858 | 0 | 0 |
| PEO [Member] | Year over Year Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (30,471,043) | 10,538,650 | 10,427,895 |
| PEO [Member] | Fair Value as of Prior Fiscal YearEnd of Option Awards and Stock Awards Granted in Prior Fiscal Years That Failed to Meet Applicable Vesting Conditions During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| Non-PEO NEO [Member] | Grant Date Fair Value of Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (18,676,467) | (4,270,687) | (3,456,374) |
| Non-PEO NEO [Member] | Fair Value at Fiscal YearEnd of Outstanding and Unvested Option Awards and Stock Awards Granted in Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 11,948,736 | 1,812,690 | 12,999,355 |
| Non-PEO NEO [Member] | Year over Year Change in Fair Value of Outstanding and Unvested Option Awards and Stock Awards Granted in Prior Fiscal Years [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (5,741,438) | 11,647,173 | 25,810,598 |
| Non-PEO NEO [Member] | Fair Value at Vesting of Option Awards and Stock Awards Granted in Fiscal Year That Vested During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 1,067,751 | 0 | 0 |
| Non-PEO NEO [Member] | Year over Year Change in Fair Value as of Vesting Date of Option Awards and Stock Awards Granted in Prior Fiscal Years For Which Applicable Vesting Conditions Were Satisfied During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (3,284,443) | 1,969,261 | 2,176,985 |
| Non-PEO NEO [Member] | Fair Value as of Prior Fiscal YearEnd of Option Awards and Stock Awards Granted in Prior Fiscal Years That Failed to Meet Applicable Vesting Conditions During Fiscal Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ 0 | $ 0 | $ 0 |
