Summary Of Significant Accounting Policies (Policy)	6 Months Ended
Mar. 27, 2020
Accounting Policies [Abstract]
Principles Of Consolidation	Principles of Consolidation The unaudited interim condensed consolidated financial statements include the accounts of Dolby Laboratories, Inc. and our wholly owned subsidiaries. In addition, we have consolidated the financial results of jointly owned affiliated companies in which our principal stockholder has a controlling interest. We report these controlling interests as a separate line in our consolidated statements of operations as net income attributable to controlling interest and in our consolidated balance sheets as a controlling interest. We eliminate all intercompany accounts and transactions upon consolidation.
Operating Segments	Operating Segments Since we operate as a single reporting segment, all required financial segment information is included in our unaudited interim condensed consolidated financial statements. This reflects the fact that our CODM, our Chief Executive Officer, evaluates our financial information and resources, and assesses the performance of these resources on a consolidated basis.
Use of Estimates	Use of Estimates The preparation of our financial statements in accordance with U.S. GAAP requires management to make certain estimates and assumptions that affect the amounts reported and disclosed in our unaudited interim condensed consolidated financial statements and accompanying notes. Significant items subject to such estimates and assumptions include estimated shipments by our licensees for which we are owed a sales–based royalty. These estimates involve the use of historical data and judgment for several key attributes including industry estimates of expected shipments, the percentage of markets using our technologies, and average sale prices. Our estimates of royalty-based revenue also take into consideration the macroeconomic effect of global events, such as the COVID-19 pandemic or other natural disasters which may impact supply chain activities as well as demand for shipments. Additional significant items subject to such estimates and assumptions include estimated selling prices for performance obligations within revenue arrangements; valuation allowances for accounts receivable; carrying values of inventories and certain property, plant, and equipment, goodwill and intangible assets; fair values of investments; accrued liabilities including liabilities for unrecognized tax benefits, deferred income tax assets and liabilities, and stock-based compensation. Actual results could differ from our estimates.
Fiscal Year	Fiscal Year Our fiscal year is a 52 or 53 week period ending on the last Friday in September. The fiscal periods presented herein include the 13 week periods ended March 27, 2020 and March 29, 2019. Our fiscal year ending September 25, 2020 (fiscal 2020) and our fiscal year ended September 27, 2019 (fiscal 2019) both consist of 52 weeks.
Reclassifications	.
Recently Issued Accounting Policies	Recently Issued Accounting Standards Adopted Standards At the beginning of fiscal 2020, we adopted the following standards: Leases. In the first quarter of fiscal 2020, we adopted ASU 2016-02, Leases (ASC 842) along with all subsequent applicable ASU clarifications and improvements, which requires lessees to recognize leases on balance sheet and disclose key information about leasing arrangements. We adopted ASC 842 using the modified retrospective transition method and used the effective date as the date of initial application. Consequently, financial information is not updated and the disclosures required under ASC 842 are not provided for dates and periods prior to implementation. ASC 842 provides a number of optional practical expedients in transition. We elected the “package of practical expedients,” which permits us not to reassess under ASC 842 our prior conclusions about lease identification, lease classification and initial direct costs. In addition, we account for lease and non-lease components as a single lease component. Operating leases are included in operating lease right-of-use assets, operating lease liabilities, and in current and non-current operating lease liabilities on our interim condensed consolidated balance sheets. As a lessee, the adoption of ASC 842 resulted in the recording of Operating lease right-of-use ("ROU") assets and Operating lease liabilities of $62.1 million and $64.6 million, respectively, as of September 28, 2019. The difference between the operating lease assets and liabilities was recorded as an adjustment to Other non-current liabilities, primarily related to deferred rent and other lease incentives. As a lessor, the adoption of ASC 842 did not have a material impact. The adoption of ASC 842 did not impact Retained Earnings. Income Taxes: Comprehensive Income. In the first quarter of fiscal 2020, we adopted ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects From Accumulated Other Comprehensive Income, which allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Act. We elected to not reclassify the stranded tax effects to retained earnings as they were not material to Dolby's consolidated financial statements. Standards Not Yet Effective Collaborative Arrangements. In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606, which clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer. In addition, ASU 2018-18 precludes an entity from presenting consideration from a transaction in a collaborative arrangement as revenue from contracts with customers if the counterparty is not a customer for that transaction. This standard will be effective for Dolby beginning September 26, 2020, and we do not currently plan to early adopt. We do not believe that this standard will have a material impact on our consolidated financial statements.

Summary Of Significant Accounting Policies (Policy)

6 Months Ended

Mar. 27, 2020

Principles of Consolidation

The unaudited interim condensed consolidated financial statements include the accounts of Dolby Laboratories, Inc. and our wholly owned subsidiaries. In addition, we have consolidated the financial results of jointly owned affiliated companies in which our principal stockholder has a controlling interest. We report these controlling interests as a separate line in our consolidated statements of operations as net income attributable to controlling interest and in our consolidated balance sheets as a controlling interest. We eliminate all intercompany accounts and transactions upon consolidation.

Operating Segments

Since we operate as a single reporting segment, all required financial segment information is included in our unaudited interim condensed consolidated financial statements. This reflects the fact that our CODM, our Chief Executive Officer, evaluates our financial information and resources, and assesses the performance of these resources on a consolidated basis.

Use of Estimates

The preparation of our financial statements in accordance with U.S. GAAP requires management to make certain estimates and assumptions that affect the amounts reported and disclosed in our unaudited interim condensed consolidated financial statements and accompanying notes.

Significant items subject to such estimates and assumptions include estimated shipments by our licensees for which we are owed a sales–based royalty. These estimates involve the use of historical data and judgment for several key attributes including industry estimates of expected shipments, the percentage of markets using our technologies, and average sale prices. Our estimates of royalty-based revenue also take into consideration the macroeconomic effect of global events, such as the COVID-19 pandemic or other natural disasters which may impact supply chain activities as well as demand for shipments.

Additional significant items subject to such estimates and assumptions include estimated selling prices for performance obligations within revenue arrangements; valuation allowances for accounts receivable; carrying values of inventories and certain property, plant, and equipment, goodwill and intangible assets; fair values of investments; accrued liabilities including liabilities for unrecognized tax benefits, deferred income tax assets and liabilities, and stock-based compensation. Actual results could differ from our estimates.

Fiscal Year

Our fiscal year is a 52 or 53 week period ending on the last Friday in September. The fiscal periods presented herein include the 13 week periods ended March 27, 2020 and March 29, 2019. Our fiscal year ending September 25, 2020 (fiscal 2020) and our fiscal year ended September 27, 2019 (fiscal 2019) both consist of 52 weeks.

Reclassifications

Recently Issued Accounting Policies

Recently Issued Accounting Standards

Adopted Standards

At the beginning of fiscal 2020, we adopted the following standards:

Leases. In the first quarter of fiscal 2020, we adopted ASU 2016-02, Leases (ASC 842) along with all subsequent applicable ASU clarifications and improvements, which requires lessees to recognize leases on balance sheet and disclose key information about leasing arrangements. We adopted ASC 842 using the modified retrospective transition method and used the effective date as the date of initial application. Consequently, financial information is not updated and the disclosures required under ASC 842 are not provided for dates and periods prior to implementation. ASC 842 provides a number of optional practical expedients in transition. We elected the “package of practical expedients,” which permits us not to reassess under ASC 842 our prior conclusions about lease identification, lease classification and initial direct costs. In addition, we account for lease and non-lease components as a single lease component.

Operating leases are included in operating lease right-of-use assets, operating lease liabilities, and in current and non-current operating lease liabilities on our interim condensed consolidated balance sheets.

As a lessee, the adoption of ASC 842 resulted in the recording of Operating lease right-of-use ("ROU") assets and Operating lease liabilities of $62.1 million and $64.6 million, respectively, as of September 28, 2019. The difference between the operating lease assets and liabilities was recorded as an adjustment to Other non-current liabilities, primarily related to deferred rent and other lease incentives. As a lessor, the adoption of ASC 842 did not have a material impact. The adoption of ASC 842 did not impact Retained Earnings.

Income Taxes: Comprehensive Income. In the first quarter of fiscal 2020, we adopted ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects From Accumulated Other Comprehensive Income, which allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Act. We elected to not reclassify the stranded tax effects to retained earnings as they were not material to Dolby's consolidated financial statements.

Standards Not Yet Effective

Collaborative Arrangements. In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606, which clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer. In addition, ASU 2018-18 precludes an entity from presenting consideration from a transaction in a collaborative arrangement as revenue from contracts with customers if the counterparty is not a customer for that transaction. This standard will be effective for Dolby beginning September 26, 2020, and we do not currently plan to early adopt. We do not believe that this standard will have a material impact on our consolidated financial statements.