Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
Mar. 30, 2012
Basis of Presentation and Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation. The accompanying unaudited condensed consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) which Harmonic Inc. (“Harmonic,” or the “Company”) considers necessary for a fair statement of the results of operations for the interim periods covered and the consolidated financial condition of the Company at the date of the balance sheets. This Quarterly Report on Form 10-Q should be read in conjunction with the Company’s audited consolidated financial statements contained in the Company’s Annual Report on Form 10-K, which was filed with the Securities and Exchange Commission on February 29, 2012 (“2011 Form 10-K”). The interim results presented herein are not necessarily indicative of the results of operations that may be expected for the full fiscal year ending December 31, 2012, or any other future period. The Company’s fiscal quarters are based on 13-week periods, except for the fourth quarter which ends on December 31. The condensed consolidated financial statements include the accounts of the Company and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. The year-end condensed balance sheet was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (“US GAAP”).
Use of Estimates	Use of Estimates. The preparation of the consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Significant Accounting Policies	Significant Accounting Policies. The Company’s significant accounting policies are described in Note 1 to its audited Consolidated Financial Statements included in its 2011 Form 10-K. There have been no significant changes to these policies during the three months ended March 30, 2012.
Fair value measurements	In May 2011, the Financial Accounting Standards Board (“FASB”) issued additional guidance on fair value disclosures. This guidance contains certain updates to the measurement guidance, as well as enhanced disclosure requirements. The most significant change in disclosures is an expansion of the information required for Level 3 measurements, including enhanced disclosure for: (1) the valuation processes used by the reporting entity; and (2) the sensitivity of the fair value measurement to changes in unobservable inputs and the interrelationships between those unobservable inputs, if any. This guidance is effective for interim and annual periods beginning on or after December 15, 2011 and early adoption is prohibited. The Company adopted these reporting requirements in the first quarter of 2012. Adoption of these new reporting requirements did not have any impact on the Company because the Company does not hold any assets or liabilities for which fair value is based on Level 3 measurements.
Presentation of comprehensive income	In June 2011, the FASB issued guidance on the presentation of comprehensive income. This guidance requires that all non-owner changes in stockholders’ equity be presented either in a single continuous statement of comprehensive income or in two separate but consecutive statements. The guidance eliminates the option to present the components of comprehensive income as part of the statement of changes in shareholders’ equity. In December 2011, the FASB issued guidance which indefinitely defers the effective date of the requirement to disclose on the face of the financial statements the effects of reclassifications out of accumulated other comprehensive income on the components of net income and other comprehensive income. The guidance must be applied retrospectively, and is effective for fiscal years, and interim periods within those years, beginning after December 15, 2011. The Company adopted this new guidance in the first quarter of 2012.
Goodwill for impairment	In September 2011, the FASB approved an accounting standard update intended to simplify how an entity tests goodwill for impairment. The amendment allows an entity to first assess qualitative factors to determine whether it is necessary to perform the two-step annual goodwill impairment test. An entity is required to perform step one only if the entity determines, based on a qualitative assessment, that it is more likely than not that its fair value is less than its carrying amount. The Company will apply this guidance when it performs its annual goodwill impairment test in the fourth quarter of 2012.

Basis of Presentation and Significant Accounting Policies [Abstract]

Use of Estimates. The preparation of the consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.

In May 2011, the Financial Accounting Standards Board (“FASB”) issued additional guidance on fair value disclosures. This guidance contains certain updates to the measurement guidance, as well as enhanced disclosure requirements. The most significant change in disclosures is an expansion of the information required for Level 3 measurements, including enhanced disclosure for: (1) the valuation processes used by the reporting entity; and (2) the sensitivity of the fair value measurement to changes in unobservable inputs and the interrelationships between those unobservable inputs, if any. This guidance is effective for interim and annual periods beginning on or after December 15, 2011 and early adoption is prohibited. The Company adopted these reporting requirements in the first quarter of 2012. Adoption of these new reporting requirements did not have any impact on the Company because the Company does not hold any assets or liabilities for which fair value is based on Level 3 measurements.

Goodwill for impairment

In September 2011, the FASB approved an accounting standard update intended to simplify how an entity tests goodwill for impairment. The amendment allows an entity to first assess qualitative factors to determine whether it is necessary to perform the two-step annual goodwill impairment test. An entity is required to perform step one only if the entity determines, based on a qualitative assessment, that it is more likely than not that its fair value is less than its carrying amount. The Company will apply this guidance when it performs its annual goodwill impairment test in the fourth quarter of 2012.