Harmonic (HLIT) 10-Q 4 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 27, 2013	Oct. 14, 2013
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	27-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'HLIT	'
Entity Registrant Name	'HARMONIC INC	'
Entity Central Index Key	'0000851310	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	100,808,712

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$93,330	$96,670
Short-term investments	75,966	104,506
Accounts receivable, net	85,069	85,920
Inventories	40,369	64,270
Deferred income taxes	20,144	21,870
Prepaid expenses and other current assets	14,757	23,636
Total current assets	329,635	396,872
Property and equipment, net	35,551	38,122
Goodwill	197,956	212,518
Intangibles, net	37,878	58,447
Other assets	16,133	11,572
Total assets	617,153	717,531
Current liabilities:	'	'
Accounts payable	19,987	25,447
Income taxes payable	577	1,797
Deferred revenue	34,115	33,235
Accrued liabilities	33,118	42,415
Total current liabilities	87,797	102,894
Income taxes payable, long-term	12,155	49,309
Other non-current liabilities	11,694	11,915
Total liabilities	111,646	164,118
Commitments and contingencies (Note 14)	'	'
Stockholders’ equity:	'	'
Preferred stock, $0.001 par value, 5,000 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.001 par value, 150,000 shares authorized; 100,901 and 114,193 shares issued and outstanding at September 27, 2013 and December 31, 2012, respectively	101	114
Additional paid-in capital	2,345,512	2,432,790
Accumulated deficit	-1,839,639	-1,879,026
Accumulated other comprehensive loss	-467	-465
Total stockholders’ equity	505,507	553,413
Total liabilities and stockholders’ equity	$617,153	$717,531

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 27, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	100,901,000	114,193,000
Common stock, shares outstanding	100,901,000	114,193,000

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Income Statement [Abstract]	'	'	'	'
Product revenue	$98,713	$97,881	$277,965	$300,731
Service revenue	24,205	22,510	63,753	58,159
Net revenue	122,918	120,391	341,718	358,890
Product cost of revenue	52,747	53,995	146,916	167,039
Service cost of revenue	13,379	11,518	33,953	31,430
Total cost of revenue	66,126	65,513	180,869	198,469
Gross profit	56,792	54,878	160,849	160,421
Operating expenses:	'	'	'	'
Research and development	24,560	25,586	75,631	77,205
Selling, general and administrative	32,527	31,132	100,220	93,862
Amortization of intangibles	2,001	2,179	6,099	6,548
Restructuring and related charges	259	0	925	0
Total operating expenses	59,347	58,897	182,875	177,615
Loss from operations	-2,555	-4,019	-22,026	-17,194
Interest income, net	47	128	141	363
Other income (expense), net	230	-164	-70	119
Loss from continuing operations before income taxes	-2,278	-4,055	-21,955	-16,712
(Benefit from) provision for income taxes	-38,953	414	-45,723	367
Income (loss) from continuing operations	36,675	-4,469	23,768	-17,079
Income (loss) from discontinued operations, net of taxes (including gain on disposal of $14,813, net of taxes, for the nine months ended September 27, 2013)	91	-3,761	15,619	1,338
Net income (loss)	$36,766	($8,230)	$39,387	($15,741)
Basic net income (loss) per share from:	'	'	'	'
Continuing operations (usd per share)	$0.36	($0.04)	$0.22	($0.15)
Discontinued operations (usd per share)	$0	($0.03)	$0.14	$0.01
Net income (loss) (usd per share)	$0.36	($0.07)	$0.36	($0.13)
Diluted net income (loss) per share from:	'	'	'	'
Continuing operations (usd per share)	$0.36	($0.04)	$0.22	($0.15)
Discontinued operations (usd per share)	$0	($0.03)	$0.14	$0.01
Net Income (loss) (usd per share)	$0.36	($0.07)	$0.36	($0.13)
Shares used in per share calculation:	'	'	'	'
Basic (in shares)	101,144	116,517	108,695	116,946
Diluted (in shares)	102,723	116,517	109,879	116,946

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012
Income Statement [Abstract]	'	'
Gain on disposal, net of taxes	$14,813	$0

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Statement of Partners' Capital [Abstract]	'	'	'	'
Net income (loss)	$36,766	($8,230)	$39,387	($15,741)
Other comprehensive income (loss), net of tax:	'	'	'	'
Changes in cumulative translation adjustments	462	403	-8	317
Foreign currency translation adjustments	462	403	-8	317
Changes in unrealized gain (loss) on investment arising during the period	52	5	11	30
Gain on investments	52	5	11	30
Other comprehensive income before tax	514	408	3	347
Income tax expense (benefit) related to items of other comprehensive income (loss)	17	3	5	-11
Other comprehensive income (loss), net of tax	497	405	-2	358
Comprehensive income (loss)	$37,263	($7,825)	$39,385	($15,383)

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012
Cash flows from operating activities:	'	'
Net income (loss)	$39,387	($15,741)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'
Amortization of intangibles	20,569	22,004
Depreciation	12,365	11,337
Stock-based compensation	11,953	14,122
Gain on sale of discontinued operations, net of tax	-14,813	0
Loss on impairment of fixed assets	149	0
Deferred income taxes	-10,647	1,627
Provision for inventories	2,813	2,466
Allowance for doubtful accounts, returns and discounts	1,161	2,012
Excess tax benefits from stock-based compensation	0	-80
Other non-cash adjustments, net	1,220	560
Changes in assets and liabilities:	'	'
Accounts receivable	-310	13,240
Inventories	10,509	-85
Prepaid expenses and other assets	8,522	1,847
Accounts payable	-5,418	364
Deferred revenue	5,127	3,307
Income taxes payable	-39,209	-1,482
Accrued and other liabilities	-8,244	-5,352
Net cash provided by operating activities	35,134	50,146
Cash flows from investing activities:	'	'
Purchases of investments	-54,773	-94,123
Proceeds from maturities of investments	50,681	44,876
Proceeds from sales of investments	31,506	30,486
Purchases of property and equipment	-11,249	-9,850
Proceeds from sale of discontinued operations, net of selling costs	43,527	0
Net cash provided by (used in) investing activities	59,692	-28,611
Cash flows from financing activities:	'	'
Payments for repurchase of common stock	-103,496	-14,388
Proceeds from issuance of common stock, net	5,355	4,922
Excess tax benefits from stock-based compensation	0	80
Net cash used in financing activities	-98,141	-9,386
Effect of exchange rate changes on cash and cash equivalents	-25	103
Net (decrease) increase in cash and cash equivalents	-3,340	12,252
Cash and cash equivalents at beginning of period	96,670	90,983
Cash and cash equivalents at end of period	$93,330	$103,235

Basis_of_Presentation_and_Sign

Basis of Presentation and Significant Accounting Policies	9 Months Ended
	Sep. 27, 2013
Accounting Policies [Abstract]	'
Basis of Presentation and Significant Accounting Policies	'
	BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES
	Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements, in the opinion of management, 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 March 1, 2013 (“2012 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, 2013, 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”).
	Discontinued Operations
	On March 5, 2013, the Company completed the sale of its cable access HFC business to Aurora Networks (“Aurora”) for $46.0 million in cash. The Condensed Consolidated Statements of Operations have been retrospectively adjusted to present the cable access HFC business as discontinued operations, as described in “Note 3, Discontinued Operations”. Unless noted otherwise, all discussions herein with respect to the Company’s unaudited condensed consolidated financial statements relate to the Company’s continuing operations.
	Use of Estimates
	The preparation of the condensed consolidated financial statements in conformity with U.S. 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
	The Company’s significant accounting policies are described in Note 2 to its audited Consolidated Financial Statements included in its 2012 Form 10-K. There have been no significant changes to these policies during the nine months ended September 27, 2013.
	Reclassifications
	From time to time the Company reclassifies certain prior period balances to conform to the current year presentation. These reclassifications have no material impact on previously reported total assets, total liabilities, stockholders’ equity, results of operations or cash flows.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	9 Months Ended
	Sep. 27, 2013
Accounting Changes and Error Corrections [Abstract]	'
Recent Accounting Pronouncements	'
	RECENT ACCOUNTING PRONOUNCEMENTS
	In December 2011, the FASB issued Accounting Standard Update (“ASU”) 2011-11, “Disclosures about offsetting assets and liabilities”. This guidance enhances disclosure requirements about the nature of an entity’s right to offset. The new guidance requires the disclosure of the gross amounts subject to rights of set-off, amounts offset in accordance with the accounting standards followed, and the related net exposure. The new guidance became effective for the Company beginning in the first quarter of fiscal 2013 and it did not have any impact on the Company’s Consolidated Financial Statements.
	In July 2012, the FASB issued ASU 2012-2, “Intangibles - Goodwill and Other”, which allows an entity to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived asset is impaired for determining whether it is necessary to perform the quantitative impairment test. This accounting standard update became effective for the Company beginning in the first quarter of fiscal 2013 and did not have any impact on the Company’s Consolidated Financial Statements.
	In February 2013, the FASB issued ASU 2013-2, “Comprehensive Income”, which requires reclassification adjustments from other comprehensive income to be presented either in the financial statements or in the notes to the financial statements. The Company adopted this new guidance in the first quarter of fiscal 2013 and included the required disclosures.
	In March 2013, the FASB issued ASU 2013-4, “Obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date”. The update provides requirements for the recognition, measurement and disclosure of an entity’s reasonable expectation of its obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. This guidance requires an entity to disclose the nature and amount of any such obligation, as well as other information about the obligation. The Company does not expect the adoption of ASU 2013-04 will have a material impact on its financial position, results of operations or cash flows. The guidance is effective for the Company beginning in the first quarter of its 2014 fiscal year and should be applied prospectively.
	In March 2013, the FASB issued ASU 2013-05, “Parent’s Accounting for the Cumulative Translation Adjustment upon De-recognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity”. The ASU addresses accounting for a cumulative translation adjustment when a parent either sells a part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or group of assets that is a nonprofit activity or a business within a foreign entity. The guidance is effective for the Company beginning in the first quarter of its 2014 fiscal year and should be applied prospectively. The Company does not expect the adoption of ASU 2013-05 will have a material impact on its financial position, results of operations or cash flows.
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists”. Under certain circumstances, unrecognized tax benefits should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. The guidance is effective for the Company beginning in the first quarter of 2014. The Company is currently evaluating the impact this guidance may have on its financial position, results of operations and cash flows.

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 27, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	DISCONTINUED OPERATIONS
	On February 18, 2013, the Company entered into an Asset Purchase Agreement with Aurora pursuant to which the Company agreed to sell its cable access HFC business for $46.0 million in cash. On March 5, 2013, the sale transaction closed and the Company received gross proceeds of $46.0 million from the sale and recorded a net gain of $15.0 million in connection with the sale in the first quarter of fiscal 2013, adjusted by ($0.2) million in the second quarter of fiscal 2013, primarily related to adjustments on inventory and fixed assets sold to Aurora, for a net gain of $14.8 million.
	In accordance with ASC 205 “Presentation of financial statements – Discontinued Operations”, a business is classified as a discontinued operation when: (i) the operations and cash flows of the business can be clearly distinguished and have been or will be eliminated from our ongoing operations; (ii) the business has either been disposed of or is classified as held for sale; and (iii) the Company will not have any significant continuing involvement in the operations of the business after the disposal transactions.
	On March 5, 2013, the Company entered into a transition services agreement (‘TSA”) with Aurora to provide contract manufacturing for up to five months and other various support, including providing order fulfillment, taking warranty calls, attending to product returns from customers, providing cost accounting analysis, receiving payments from customers and remitting such payments to Aurora for up to two months. The TSA fees are a fixed amount per month and were determined based on the Company’s estimated cost of delivering the transition services. In addition, on April 24, 2013, the Company and Aurora signed a sublease agreement for the Company’s Milpitas warehouse for the remaining period of the lease. The Company and Aurora later agreed to limit the services provided under the agreement to sales order processing support and quote support through May 2013, warehouse facilities support through July 2013, accounts payable support through June 2013, and accounts receivable collection support through October 2013, and the TSA fees were amended accordingly.
	The Company determined that the cash flows generated from these transactions are both insignificant and are considered indirect cash flows. As a result, the sale of the cable access HFC business is appropriately presented as discontinued operations. The TSA billing to Aurora in the three and nine months ended September 27, 2013 was $48,000 and $977,000, respectively, and it was recorded in the Condensed Consolidated Statements of Operations under income from continuing operations as an offset to the expenses incurred to deliver the transition services. The table below provides details on the income statement caption under which the TSA billing was recorded (in thousands):
		Three months ended			Nine months ended
		27-Sep-13
	Product cost of revenue	$	41		$	577
	Research and development	—			21
	Selling, general and administrative	7			379
	Total TSA billing to Aurora	$	48		$	977
	Included within the “Prepaid expenses and other current assets” ending balance at September 27, 2013 on the Condensed Consolidated Balance Sheet is $0.2 million in receivables from customers invoiced on Aurora’s behalf. Included within the “Accrued liabilities” ending balance at September 27, 2013 is $0.2 million due to Aurora primarily for invoicing to customers made on Aurora’s behalf. There is no outstanding payable to third party vendors on Aurora’s behalf and there is no outstanding receivable from Aurora for purchases made on its behalf, as the Company ceased making purchases on Aurora’s behalf at the end of May 2013.
	The Company recorded a gain of $14.8 million for the nine months ended September 27, 2013, in connection with the sale of the cable access HFC business, calculated as follows (in thousands):
	Gross Proceeds				$	46,000
	Less : Carrying value of net assets
	Inventories, net	$	10,579
	Prepaid expenses and other current assets	612
	Property and equipment, net	1,180
	Goodwill de-recognized	14,547
	Deferred revenue	(4,499		)
	Accrued liabilities	(939		)
	Total net assets sold and de-recognized				$	21,480
	Less : Selling cost				$	2,473
	Less : Tax effect				$	7,234
	Gain on disposal, net of taxes				$	14,813
	Since the Company has one reporting unit, upon the sale of the cable access HFC business, approximately $14.5 million of the carrying value of goodwill was allocated to the cable access HFC business based on the relative fair value of the cable access HFC business to the fair value of the Company. The remaining carrying value of goodwill was tested for impairment, and the Company determined that goodwill was not impaired as of March 29, 2013.
	The results of operations associated with the cable access HFC business are presented as discontinued operations in the Company’s Condensed Consolidated Statements of Operations for all periods presented. Revenue and the components of net income related to the discontinued operations for the three and nine months ended September 27, 2013 and September 28, 2012 were as follows:
		Three months ended						Nine months ended
		27-Sep-13			28-Sep-12			27-Sep-13			28-Sep-12
	Revenue	$	161		$	16,291		$	9,717		$	38,147
	Operating income	$	154		$	3,070		$	669		$	5,193
	Less : provision for (benefit from) income taxes	57			6,831			(137		)	3,855
	Add : Gain (loss) on disposal, net of taxes	(6		)	—			14,813			—
	Income (loss) from discontinued operations, net of taxes	$	91		$	(3,761	)	$	15,619		$	1,338

ShortTerm_Investments

Short-Term Investments	9 Months Ended
	Sep. 27, 2013
Cash and Cash Equivalents [Abstract]	'
Short-Term Investments	'
	SHORT-TERM INVESTMENTS
	The following table summarizes the Company’s short-term investments (in thousands):
		Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair Value
				Gains		Losses
	As of September 27, 2013
	State, municipal and local government agencies bonds	$	36,195	$	41	$	(3	)	$	36,233
	Corporate bonds	32,376		16		(11		)	32,381
	Commercial paper	3,348		—		—			3,348
	U.S. federal government bonds	4,001		3		—			4,004
	Total short-term investments	$	75,920	$	60	$	(14	)	$	75,966
	As of December 31, 2012
	Certificates of deposit	$	1,603	$	—	$	—		$	1,603
	State, municipal and local government agencies bonds	59,009		45		(4		)	59,050
	Corporate bonds	31,568		4		(10		)	31,562
	Commercial paper	10,287		1		—			10,288
	U.S. federal government bonds	2,003		—		—			2,003
	Total short-term investments	$	104,470	$	50	$	(14	)	$	104,506
	The following table summarizes the maturities of the Company’s short-term investments (in thousands):
		27-Sep-13		31-Dec-12
	Less than one year	$	50,782	$	76,779
	Due in 1 - 2 years	25,184		27,727
	Total short-term investments	$	75,966	$	104,506
	Realized gains and losses from the sale of investments for the three and nine months ended September 27, 2013 and September 28, 2012 were not material.
	Impairment of Investments
	The Company monitors its investment portfolio for impairment on a periodic basis. In the event that the carrying value of an investment exceeds its fair value and the decline in value is determined to be other-than-temporary, an impairment charge is recorded and a new cost basis for the investment is established. A decline of fair value below amortized costs of debt securities is considered other-than-temporary if the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security before recovery of the entire amortized cost basis. At the present time, the Company does not intend to sell its investments that have unrealized losses in accumulated other comprehensive loss. In addition, the Company does not believe that it is more likely than not that it will be required to sell its investments that have unrealized losses in accumulated other comprehensive loss before the Company recovers the principal amounts invested. The Company believes that the unrealized losses are temporary and do not require an other-than-temporary impairment, based on its evaluation of available evidence as of September 27, 2013.
	As of September 27, 2013, there were no individual available-for-sale securities in a material unrealized loss position and the amount of unrealized losses on the total investment balance was insignificant.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 27, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	FAIR VALUE MEASUREMENTS
	The applicable accounting guidance establishes a framework for measuring fair value and requires disclosure about the fair value measurements of assets and liabilities. This guidance requires the Company to classify and disclose assets and liabilities measured at fair value on a recurring basis, as well as fair value measurements of assets and liabilities measured on a nonrecurring basis in periods subsequent to initial measurement, in a three-tier fair value hierarchy as described below.
	The guidance defines fair value as the exchange price that would be received for an asset or paid to transfer a liability, in the principal or most advantageous market for the asset or liability, in an orderly transaction between market participants on the measurement date.
	Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The guidance describes three levels of inputs that may be used to measure fair value:
	•	Level 1 — Observable inputs that reflect quoted prices for identical assets or liabilities in active markets.
	•	Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company primarily uses broker quotes for valuation of its short-term investments. The forward exchange contracts are classified as Level 2 because they are valued using quoted market prices and other observable data for similar instruments in an active market.
	•	Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	The Company uses the market approach to measure fair value for its financial assets and liabilities. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. During the nine months ended September 27, 2013, there were no nonrecurring fair value measurements of assets and liabilities subsequent to initial recognition.
	The following table sets forth the fair value of the Company’s financial assets and liabilities measured at fair value based on the three-tier fair value hierarchy (in thousands):
		Level 1		Level 2		Level 3		Total
	As of September 27, 2013
	Cash equivalents
	Money market funds	$	58,220	$	—	$	—	$	58,220
	Short-term investments
	State, municipal and local government agencies bonds	—		36,233		—		36,233
	Corporate bonds	—		32,381		—		32,381
	Commercial paper	—		3,348		—		3,348
	U.S. federal government bonds	4,004		—		—		4,004
	Prepaids and other current assets
	Foreign exchange forward contracts	—		5		—		5
	Total assets measured and recorded at fair value	$	62,224	$	71,967	$	—	$	134,191
	Accrued liabilities
	Foreign exchange forward contracts	$	—	$	381	$	—	$	381
	Total liabilities measured and recorded at fair value	$	—	$	381	$	—	$	381
		Level 1		Level 2		Level 3		Total
	As of December 31, 2012
	Cash equivalents
	Money market funds	$	54,923	$	—	$	—	$	54,923
	Corporate bonds with maturity less than 90 days	—		3,614		—		3,614
	U.S. federal government bonds with maturity less than 90 days	3,005		—		—		3,005
	Short-term investments
	Certificates of deposit	—		1,603		—		1,603
	State, municipal and local government agencies bonds	—		59,050		—		59,050
	Corporate bonds	—		31,562		—		31,562
	Commercial paper	—		10,288		—		10,288
	U.S. federal government bonds	2,003		—		—		2,003
	Prepaids and other current assets
	Foreign exchange forward contracts	—		344		—		344
	Total assets measured and recorded at fair value	$	59,931	$	106,461	$	—	$	166,392
	Accrued liabilities
	Foreign exchange forward contracts	$	—	$	143	$	—	$	143
	Total liabilities measured and recorded at fair value	$	—	$	143	$	—	$	143

Balance_Sheet_Components

Balance Sheet Components	9 Months Ended
	Sep. 27, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Balance Sheet Components	'
	BALANCE SHEET COMPONENTS
	The following tables provide details of selected balance sheet components (in thousands):
		27-Sep-13			31-Dec-12
	Accounts receivable, net:
	Accounts receivable	$	94,283		$	95,515
	Less: allowances for doubtful accounts, returns and discounts	(9,214		)	(9,595		)
	Accounts receivable, net	$	85,069		$	85,920
	Inventories:
	Raw materials	$	3,188		$	10,731
	Work-in-process	1,378			4,347
	Finished goods	35,803			49,192
	Total inventories	$	40,369		$	64,270
	Property and equipment, net:
	Furniture and fixtures	$	8,104		$	7,856
	Machinery and equipment	111,182			108,262
	Leasehold improvements	7,686			7,612
	Property and equipment, gross	126,972			123,730
	Less: accumulated depreciation and amortization	(91,421		)	(85,608		)
	Property and equipment, net	$	35,551		$	38,122

Goodwill_and_Identified_Intang

Goodwill and Identified Intangible Assets	9 Months Ended
	Sep. 27, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Identified Intangible Assets	'
	GOODWILL AND IDENTIFIED INTANGIBLE ASSETS
	The changes in the carrying amount of goodwill for the nine months ended September 27, 2013 are as follows (in thousands):
	Balance at beginning of period	$	212,518
	Reduction in goodwill associated with the sale of the cable access HFC Business	(14,547		)
	Foreign currency translation adjustment	(15		)
	Balance at end of period	$	197,956
	The following is a summary of identified intangible assets (in thousands):
		27-Sep-13								31-Dec-12
		Gross Carrying			Accumulated			Net Carrying		Gross Carrying		Accumulated			Net Carrying
		Amount			Amortization			Amount		Amount		Amortization			Amount
	Identifiable intangibles:
	Developed core technology	$	136,145		$	(116,918	)	$	19,227	$	136,145	$	(102,449	)	$	33,696
	Customer relationships/contracts	67,098			(52,381		)	14,717		67,098		(48,150		)	18,948
	Trademarks and tradenames	11,361			(10,210		)	1,151		11,361		(9,145		)	2,216
	Maintenance agreements and related relationships	7,100			(4,317		)	2,783		7,100		(3,513		)	3,587
	Total identifiable intangibles	$	221,704		$	(183,826	)	$	37,878	$	221,704	$	(163,257	)	$	58,447
	Amortization expense for the identifiable purchased intangible assets for the three and nine months ended September 27, 2013 and September 28, 2012 was allocated as follows (in thousands):
		Three months ended						Nine months ended
		September 27,			September 28,			September 27,		September 28,
		2013			2012			2013		2012
	Included in cost of revenue	$	4,763		$	5,048		$	14,470	$	15,456
	Included in operating expenses	2,001			2,179			6,099		6,548
	Total amortization expense	$	6,764		$	7,227		$	20,569	$	22,004
	The estimated future amortization expense of purchased intangible assets with definite lives is as follows (in thousands):
		Cost of Revenue			Operating			Total
					Expenses
	Year ended December 31,
	2013 (remaining 3 months)	$	4,763		$	1,997		$	6,760
	2014	13,745			6,775			20,520
	2015	719			5,783			6,502
	2016	—			4,096			4,096
	2017	—			—			—
	Total future amortization expense	$	19,227		$	18,651		$	37,878

Restructuring_and_Related_Char

Restructuring and Related Charges	9 Months Ended
	Sep. 27, 2013
Restructuring and Related Activities [Abstract]	'
Restructuring and Related Charges	'
	RESTRUCTURING AND RELATED CHARGES
	Omneon Restructuring
	The Company has restructuring accruals for excess lease facilities related to the closure of the Omneon headquarters in Sunnyvale, California. The accrual was based on future rent payments, net of expected sublease income, to be made through the end of the lease term in June 2013. The following table summarizes the activity in the Omneon restructuring accrual during the nine months ended September 27, 2013 (in thousands):
		Excess
		Facilities
	Balance at December 31, 2012	$	869
	Cash payments	(897		)
	Accretion	28
	Balance at September 27, 2013	—
	HFC Restructuring
	As a result of the sale of the cable access HFC business in March 2013, the Company recorded $16,000 and $617,000 of restructuring charges under “Income from discontinued operations” in the three and nine months ended September 27, 2013, respectively. The restructuring charge for the nine months ended September 27, 2013 consisted of $522,000 of severance and benefits and $95,000 of contract termination costs. The severance and benefits are related to the termination of nine of the Company's employees by the Company as a result of the sale of the HFC business, and the reimbursement to Aurora, pursuant to the amended TSA, of severance payable by Aurora as a result of its subsequent termination of ten U.S. employees hired from the Company, in connection with Aurora's purchase of the HFC business. Three of the employees terminated by the Company were required to work to the end of the term of the TSA and, therefore, the Company recorded their severance ratably over their service period. The following table summarizes the activity in the HFC restructuring accrual during the nine months ended September 27, 2013 (in thousands):
		Severance			Contract			Total
					Termination
	Balance at December 31, 2012	$	—		$	—		$	—
	Restructuring charges in discontinued operations	403			124			527
	Adjustments to restructuring provisions	119			(29		)	90
	Cash payments	(492		)	(95		)	(587		)
	Balance at September 27, 2013	30			—			30
	The Company anticipates that the remaining restructuring accrual balance of $30,000 will be paid out by the end of the fourth quarter of fiscal 2013.
	Harmonic 2013 Restructuring
	The Company implemented a series of restructuring plans in fiscal 2013 to reduce costs and improve efficiencies. As a result, the Company recorded restructuring charges of $0.6 million and $1.5 million in the three and nine months ended September 27, 2013, respectively. For the nine months ended September 27, 2013, the restructuring charges consisted of severance and benefits of $1.2 million related to the termination of sixty-three employees worldwide. In addition, the Company wrote–down, to its estimated net realizable value, leasehold improvements and furniture related to its Milpitas warehouse by $149,000, and wrote-down inventory to reflect $151,000 of obsolete inventories arising from the restructuring of its Israel facilities. The following table summarizes the activity in the Harmonic 2013 restructuring accrual during the nine months ended September 27, 2013 (in thousands):
		Severance			Impairment			Obsolete inventories			Total
					of Leasehold
					Improvement
	Balance at December 31, 2012	$	—		$	—		$	—		$	—
	Restructuring charges in continuing operations	1,089			101			151			1,341
	Adjustments to restructuring provisions	66			48			—			114
	Cash payments	(1,060		)	—			—			(1,060		)
	Non-cash write-offs	—			(149		)	(151		)	(300		)
	Balance at September 27, 2013	95			—			—			95
	Of the restructuring charges in the nine months ended September 27, 2013, $530,000 is included in “Product cost of revenue” and the remaining $925,000 is included in “Operating expenses-restructuring and related charges” in the Condensed Consolidated Statements of Operations. The Company anticipates that the remaining restructuring accrual balance of $95,000 will be paid out or used by the end of the fourth quarter of fiscal 2013.

Credit_Facilities

Credit Facilities	9 Months Ended
	Sep. 27, 2013
Debt Disclosure [Abstract]	'
Credit Facilities	'
	CREDIT FACILITIES
	Harmonic has a bank line of credit facility with Silicon Valley Bank that provides for borrowings of up to $10.0 million and matures on August 22, 2014. As of September 27, 2013, other than standby letters of credit (Note 14), there were no amounts outstanding under the line of credit facility, and there were no borrowings during the nine months ended September 27, 2013. As of September 27, 2013, the amount available for borrowing under this facility, net of $0.2 million of standby letters of credit, was $9.8 million.
	This facility, which became effective in August 2011 and was amended in August 2012, contains a financial covenant that requires Harmonic to maintain a ratio of unrestricted cash, accounts receivable and short term investments to current liabilities (less deferred revenue) of at least 1.75 to 1.00. As of September 27, 2013, the Company’s ratio under that covenant was 4.71 to 1. In the event of noncompliance by Harmonic with the covenants under the facility, including the financial covenant referenced above, Silicon Valley Bank would be entitled to exercise its remedies under the facility, including declaring all obligations immediately due and payable. As of September 27, 2013, Harmonic was in compliance with the covenants under the line of credit facility. Borrowings pursuant to the line would bear interest at the bank’s prime rate (3.25% at September 27, 2013,) or at LIBOR for the desired borrowing period (an annualized rate of 0.18% for a one month borrowing period at September 27, 2013) plus 1.75%, or 1.93%. Borrowings are not collateralized.

Employee_Benefit_Plans

Employee Benefit Plans	9 Months Ended
	Sep. 27, 2013
Postemployment Benefits [Abstract]	'
Employee Benefit Plans	'
	EMPLOYEE BENEFIT PLANS
	Harmonic grants stock options and restricted stock units (“RSUs”) pursuant to stockholder approved equity incentive plans. These equity incentive plans are described in detail in Note 13, “Employee Benefit Plans”, of Notes to Consolidated Financial Statements in the 2012 Form 10-K
	Stock Options and Restricted Stock Units
	The following table summarizes the Company’s stock option and RSU unit activity during the nine months ended September 27, 2013 (in thousands, except per share amounts):
				Stock Options Outstanding						Restricted Stock Units Outstanding
		Shares		Number			Weighted			Number		Weighted
		Available for		of			Average			of		Average
		Grant		Shares			Exercise Price			Units		Grant
												Date Fair
												Value
	Balance at December 31, 2012	10,155		8,900			$	6.83		3,938		$	6.44
	Authorized	—		—			—			—		—
	Granted	(3,361	)	1,360			5.81			1,333		5.84
	Options exercised	—		(788	)		4.15			—		—
	Shares released	—		—			—			(1,622	)	6.28
	Forfeited or cancelled	2,015		(1,461	)		6.92			(418	)	6.51
	Balance at September 27, 2013	8,809		8,011			$	6.9		3,231		$	6.27
	The following table summarizes information about stock options outstanding as of September 27, 2013 (in thousands, except per share amounts):
		Number		Weighted				Weighted	Aggregate
		of		Average				Average	Intrinsic
		Shares		Exercise				Remaining	Value
				Price				Contractual
								Term (Years)
	Vested and expected to vest	7,719		$	6.94			3.3	$	9,532
	Exercisable	5,604		7.27				2.3	5,516
	The intrinsic value of options vested and expected to vest and exercisable as of September 27, 2013 is calculated based on the difference between the exercise price and the fair value of the Company’s common stock as of September 27, 2013. The intrinsic value of options exercised during the three and nine months ended September 27, 2013 was $1.1 million and $2.0 million, respectively. The intrinsic value of options exercised during the three and nine months ended September 28, 2012 was $0.1 million and $0.6 million, respectively. The intrinsic value of options exercised is calculated based on the difference between the exercise price and the fair value of the Company’s common stock as of the exercise date.
	The following table summarizes information about restricted stock units outstanding as of September 27, 2013 (in thousands, except per share amounts):
		Number of		Weighted		Aggregate
		Shares		Average		Fair
		Underlying		Remaining		Value (1)
		Restricted		Vesting
		Stock		Period
		Units		(Years)
	Vested and expected to vest	2,934		0.9		$	22,824
	-1	Represents the fair value of the Company’s common stock as of September 27, 2013, times the number of restricted stock units vested and expected to vest as of the same date.
	Employee Stock Purchase Plan
	The 2002 Employee Stock Purchase Plan (“ESPP”) provides for the issuance of common stock purchase rights to employees of the Company. The ESPP is intended to qualify as an “employee stock purchase plan” under Section 423 of the Internal Revenue Code. The ESPP enables employees to purchase shares at 85% of the fair market value of the common stock at the beginning or end of the offering period, whichever is lower. Offering periods generally begin on the first trading day on or after January 1 and July 1 of each year. Employees may participate through payroll deductions of 1% to 10% of their earnings. In the event that there are insufficient shares in the plan to fully fund the issuance, the available shares will be allocated across all participants based on their contributions relative to the total contributions received for the offering period.
	There was a shortage of approved shares in the ESPP to fund the total employee contributions from January 2, 2013 to June 30, 2013. The shares available in the plan were sufficient to fund approximately 53% of the total contributions. As a result, the shares available were issued ratably to the participants based on each of their contributions during the offering period, relative to the total contributions received from all participants. The participants were refunded the remaining 47% of their contributions and the ESPP was suspended for the second half of 2013. The Company’s stockholders approved a 1,000,000 share increase in the authorized shares for the ESPP during the Company’s annual meeting on August 14, 2013, and contributions under the ESPP will resume in January 2014.
	401-K Plan
	Harmonic has a retirement/savings plan which qualifies as a thrift plan under Section 401(k) of the Internal Revenue Code. This plan allows participants to contribute up to the applicable Internal Revenue Code limitations under the plan. Harmonic has made discretionary contributions to the plan of 25% of the first 4% contributed by eligible participants, up to a maximum contribution per participant of $1,000 per year. Harmonic’s contributions were suspended from 2009 through 2012, but have been renewed, on the same basis, for 2013.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 27, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation	'
	STOCK-BASED COMPENSATION
	Stock-based compensation expense consists primarily of expenses for stock options and restricted stock units granted to employees and shares issued under the ESPP. The following table summarizes stock-based compensation expense (in thousands):
		Three months ended							Nine months ended
		September 27,			September 28,				September 27,			September 28,
		2013			2012				2013			2012
	Stock-based compensation in:
	Cost of revenue	$	605		$	659			$	1,838		$	2,176
	Research and development expense	1,076			1,450				3,400			4,755
	Selling, general and administrative expense	2,264			2,388				6,628			6,816
	Total stock-based compensation in operating expense	3,340			3,838				10,028			11,571
	Total stock-based compensation	$	3,945		$	4,497			$	11,866		$	13,747
	Stock Options
	The Company estimated the fair value of all employee stock options using a Black-Scholes valuation model with the following weighted average assumptions:
		Three months ended					Nine months ended
		September 27,		September 28,			September 27,			September 28,
		2013		2012			2013			2012
	Expected term (years)	4.7		4.7			4.7			4.7
	Volatility	46	%	54	%		51	%		56	%
	Risk-free interest rate	1.5	%	0.7	%		0.8	%		0.9	%
	Expected dividends	0	%	0	%		0	%		0	%
	The expected term represents the weighted-average period that the stock options are expected to remain outstanding. The computation of the expected term was determined based on historical experience of similar awards, giving consideration to the contractual terms of the stock-based awards, vesting schedules and expectations of future employee behavior. The Company uses its historical volatility for a period equivalent to the expected term of the options to estimate the expected volatility. The risk-free interest rate that the Company uses in the Black-Scholes option valuation model is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation model.
	The Company is required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and records stock-based compensation expense only for those awards that are expected to vest. All stock-based payment awards are amortized on a straight-line basis over the requisite service periods of the awards, which are generally the vesting periods.
	The weighted-average fair value per share of options granted was $3.02 and $1.89 for the three months ended September 27, 2013 and September 28, 2012, respectively. The weighted-average fair value per share of options granted was $2.51 and $2.66 for the nine months ended September 27, 2013 and September 28, 2012, respectively.
	The fair value of all stock options vested during the three months ended September 27, 2013 and September 28, 2012 was $0.8 million and $0.8 million, respectively. The fair value of all stock options vested during the nine months ended September 27, 2013 and September 28, 2012 was $2.8 million and $3.8 million, respectively.
	The total realized tax benefit attributable to stock options exercised during the nine months ended September 28, 2012, in jurisdictions where this expense is deductible for tax purposes, was $80,000. The Company did not recognize any tax benefit attributable to stock options exercised during the nine months ended September 27, 2013.
	Restricted Stock Units
	The estimated fair value of restricted stock units is based on the market price of the Company’s common stock on the grant date. The fair value of all restricted stock units issued during the three months ended September 27, 2013 and September 28, 2012 was $2.8 million and $2.6 million, respectively. The fair value of all restricted stock units issued during the nine months ended September 27, 2013 and September 28, 2012 was $10.2 million and $10.3 million, respectively.
	Employee Stock Purchase Plan
	The value of the stock purchase rights under the ESPP consists of: (1) the 15% discount on the purchase of the stock; (2) 85% of the fair value of the call option; and (3) 15% of the fair value of the put option. The call option and put option were valued using the Black-Scholes option pricing model with the following assumptions:
		Purchase Period Ending		Purchase Period Ending
		June 30,		June 30,			December 31,
		2013		2012			2012
	Expected term (years)	0.49		0.5			0.5
	Volatility	30	%	53	%		46	%
	Risk-free interest rate	0.2	%	0.2	%		0.2	%
	Expected dividends	0	%	0	%		0	%
	The expected term represents the period of time from the beginning of the offering period to the purchase date. The Company uses its historical volatility for a period equivalent to the expected term of the options to estimate the expected volatility. The risk-free interest rate that the Company uses in the Black-Scholes option valuation model is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation model.
	The fair value per share of stock purchase rights under the ESPP granted for the purchase period ended June 30, 2013 and June 30, 2012, was $1.23 and $1.51, respectively. The fair value per share of stock purchase rights under the ESPP granted for the purchase period ended December 31, 2012 was $1.19. The ESPP is suspended for the second half of 2013 due to all authorized shares under the plan having been issued through the offering period ended June 30, 2013. The Company’s stockholders approved a 1,000,000 share increase in the authorized shares for the ESPP during the Company’s annual meeting on August 14, 2013, and contributions under the ESPP will resume in January 2014. As a result, the Company will not have any stock-based compensation expense in the second half of fiscal 2013 related to the ESPP.
	Unrecognized Stock-Based Compensation
	As of September 27, 2013, total unamortized stock-based compensation cost related to unvested stock options and restricted stock units was $20.7 million. This amount will be recognized as expense using the straight-line attribution method over the remaining weighted-average amortization period of 2.0 years.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 27, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	INCOME TAXES
	The income tax provision includes federal, state and local and foreign income taxes and is based on the application of a forecasted annual income tax rate applied to the current quarter’s year-to-date pre-tax income (loss). In determining the estimated annual effective income tax rate, the Company estimates the annual impact of certain factors, including projections of the Company’s annual earnings, taxing jurisdictions in which the earnings will be generated, state and local income taxes, the Company’s ability to use tax credits and net operating loss carryforwards, and available tax planning alternatives. Discrete items, including the effect of changes in tax laws, tax rates, and certain circumstances with respect to valuation allowances or other unusual or non-recurring tax adjustments, are reflected in the period in which they occur as an addition to, or reduction from, the income tax provision, rather than being included in the estimated annual effective income tax rate.
	For the nine months ended September 27, 2013, the difference between the recorded benefit from income taxes and the tax provision, based on the federal statutory rate of 35%, was primarily attributable to the net of various discrete items, non-deductible amortization on foreign intangibles, the differential in foreign tax rates, the federal research and development tax credit, and non-deductible stock-based compensation expense. The discrete items recorded in the first nine months of 2013 primarily related to the benefit associated with the reversal of previously recorded federal and, to a lesser extent, foreign income taxes as a result of the expiration of the applicable statutes of limitations in the U.S. for 2008 and 2009 and in foreign jurisdictions for various years, and the benefit associated with the reinstatement of the federal research and development tax credit for 2012, offset partially by the increase in the valuation allowance on the California research and development tax credit and accrued interest on uncertain tax positions.
	For the nine months ended September 28, 2012, the difference between the recorded provision for income taxes and the tax provision, based on the federal statutory rate of 35%, was primarily attributable to the net of various discrete items, the differential in foreign tax rates, non-deductible stock-based compensation expense, and non-deductible amortization on foreign intangibles. The discrete items recorded in the first nine months of 2012 primarily related to the increase in the valuation allowance on the California research and development tax credit and accrued interest on uncertain tax positions, offset partially by the benefit associated with the reversal of previously recorded foreign income taxes due to the expiration of the statute of limitation in the foreign jurisdictions.
	The Company files federal, state, and foreign income tax returns in jurisdictions with varying statutes of limitations during which such tax returns may be audited and adjusted by the relevant tax authorities. The U.S. Internal Revenue Service has concluded its audit for the 2008 and 2009 tax years. In addition, the statute of limitations on the Company's 2008 and 2009 U.S. corporate income tax return expired in September 2013 and, as a result, in the third quarter of 2013, the Company recorded a discrete net tax benefit of $38.4 million related to the release of tax reserves for uncertain tax positions for those tax years. The 2010 through 2012 tax years generally remain subject to examination by federal and most state tax authorities. In significant foreign jurisdictions, the 2006 through 2012 tax years generally remain subject to examination by their respective tax authorities. In the third quarter of 2013, the Israeli tax authority concluded its audit of a subsidiary of the Company for the years 2007 through 2010, and a final settlement was made with the Israeli tax authority. The settlement did not have a material impact on the Company's overall tax expense, deferred tax assets realization, effective tax rate, operating results or cash flow.
	In compliance with applicable guidance for accounting for uncertainty in income taxes, the Company had gross unrecognized tax benefits, which include interest and penalties, of approximately $59.2 million as of December 31, 2012, and approximately $22.3 million as of September 27, 2013. If all of the unrecognized tax benefits at September 27, 2013 were recognized, the entire amount would impact the provision for income taxes. The unrecognized tax benefits may decrease significantly within the next 12 months if a related statute of limitations that is currently set to expire during that period is not extended.
	The realization of our deferred tax assets is dependent upon the generation of sufficient U.S and foreign taxable income in the future to offset against those assets. We may not have sufficient taxable income in the future to determine that we will be able to realize some significant portion of our deferred tax assets. As a result, an additional valuation allowance against our deferred tax assets may be required in the period in which such a determination is made, and our operating results could be materially and adversely impacted in the period of adjustment.
	The Company recognizes interest and possible penalties related to uncertain tax positions in income tax expense. During the nine months ended September 27, 2013, as a result of the expiration of the applicable statutes of limitations in the U.S. for 2008 and 2009 and in foreign jurisdictions for various years, the Company recorded a net decrease of $5.8 million for interest and possible penalties related to uncertain tax positions, resulting in a balance at September 27, 2013 of $1.4 million.

Income_Loss_Per_Share

Income (Loss) Per Share	9 Months Ended
	Sep. 27, 2013
Earnings Per Share [Abstract]	'
Income (Loss) Per Share	'
	INCOME (LOSS) PER SHARE
	The following table sets forth the computation of the basic and diluted net loss per share (in thousands, except per share amounts):
		Three months ended						Nine months ended
		September 27,			September 28,			September 27,		September 28,
		2013			2012			2013		2012
	Numerator:
	Income (loss) from continuing operations	$	36,675		$	(4,469	)	$	23,768	$	(17,079	)
	Income (loss) from discontinued operations	91			(3,761		)	15,619		1,338
	Net income (loss)	$	36,766		$	(8,230	)	$	39,387	$	(15,741	)
	Denominator:
	Weighted average number of common shares outstanding
	Basic	101,144			116,517			108,695		116,946
	Effect of dilutive securities from stock options, restricted stock units and ESPP	1,579			—			1,184		—
	Diluted	102,723			116,517			109,879		116,946
	Basic net income (loss) per share from:
	Continuing operations	$	0.36		$	(0.04	)	$	0.22	$	(0.15	)
	Discontinued operations	$	—		(0.03		)	0.14		0.01
	Net Income (loss)	$	0.36		$	(0.07	)	$	0.36	$	(0.13	)
	Diluted net income (loss) per share from:
	Continuing operations	$	0.36		$	(0.04	)	$	0.22	$	(0.15	)
	Discontinued operations	$	—		$	(0.03	)	$	0.14	$	0.01
	Net Income (loss)	$	0.36		$	(0.07	)	$	0.36	$	(0.13	)
	The following table sets forth the potentially dilutive shares from stock options, restricted stock units and the ESPP, for the periods presented, that were excluded from the net income (loss) per share computations because their effect was anti-dilutive (in thousands):
		Three months ended					Nine months ended
		September 27,		September 28,			September 27,		September 28,
		2013		2012			2013		2012
	Potentially dilutive equity awards outstanding	6,144		13,608			10,447		13,382

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 27, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	COMMITMENTS AND CONTINGENCIES
	Leases
	Future minimum lease payments under non-cancelable operating leases as of September 27, 2013, after giving effect to $0.5 million of future sublease income from Aurora, are as follows (in thousands):
	Years ending December 31,
	2013 (remaining three months)	$	2,645
	2014	9,600
	2015	9,047
	2016	7,811
	2017	7,659
	Thereafter	21,157
	Total	$	57,919
	Warranties
	The Company accrues for estimated warranty costs at the time of product shipment. Management periodically reviews the estimated fair value of its warranty liability and records adjustments based on the terms of warranties provided to customers, historical and anticipated warranty claims experience, and estimates of the timing and cost of warranty claims. Activity for the Company’s warranty accrual, which is included in accrued liabilities, is summarized below (in thousands):
		Three months ended						Nine months ended
		September 27,			September 28,			September 27,			September 28,
		2013			2012			2013			2012
	Balance at beginning of period	$	3,228		$	4,725		$	4,292		$	5,558
	Transfer to Aurora as part of the sale of discontinued operations	—			—			(939		)	—
	Accrual for current period warranties	1,991			1,314			5,333			4,407
	Warranty costs incurred	(1,705		)	(1,677		)	(5,172		)	(5,603		)
	Balance at end of period	$	3,514		$	4,362		$	3,514		$	4,362
	Purchase Commitments with Contract Manufacturers and Other Suppliers
	The Company relies on a limited number of contract manufacturers and suppliers to provide manufacturing services for a substantial majority of its products. In addition, some components, sub-assemblies and modules are obtained from a sole supplier or limited group of suppliers. During the normal course of business, in order to reduce manufacturing lead times and ensure adequate component supply, the Company enters into agreements with certain contract manufacturers and suppliers that allow them to procure inventory based upon criteria as defined by the Company. The Company had approximately $20.8 million of non-cancelable purchase commitments with contract manufacturers and other suppliers as of September 27, 2013.
	Standby Letters of Credit
	As of September 27, 2013, the Company’s financial guarantees consisted of standby letters of credit outstanding, which were principally related to performance bonds and state requirements imposed on employers. The maximum amount of potential future payments under these arrangements was $0.2 million as of September 27, 2013.
	Indemnification
	Harmonic is obligated to indemnify its officers and the members of its Board of Directors pursuant to its bylaws and contractual indemnity agreements. Harmonic also indemnifies some of its suppliers and most of its customers for specified intellectual property matters pursuant to certain contractual arrangements, subject to certain limitations. The scope of these indemnities varies, but, in some instances, includes indemnification for damages and expenses (including reasonable attorneys’ fees). There have been no amounts accrued in respect of these indemnification provisions through September 27, 2013.
	Guarantees
	The Company has $0.5 million of guarantees in Israel as of September 27, 2013, with the majority relating to rent obligations for buildings used by its Israeli subsidiaries.
	Legal proceedings
	In October 2011, Avid Technology, Inc. (“Avid”) filed a complaint in the United States District Court for the District of Delaware alleging that Harmonic’s Media Grid product infringes two patents held by Avid. A jury trial on this initial complaint is scheduled for January 2014. In June 2012, Avid served a subsequent complaint alleging that Harmonic’s Spectrum product infringes one patent held by Avid. In September 2013, the U.S. Patent Trial and Appeal Board authorized an inter partes review to be instituted as to claims of the patent asserted in this second complaint. The complaints seek injunctive relief and unspecified damages.
	In November 2012, FastVDO served a lawsuit on Harmonic, alleging infringement of a patent allegedly essential to the H.264 standard and that Harmonic encoders, transcoders, software and servers that use H.264 infringe their patent. The complaint seeks injunctive relief and unspecified damages.
	At this time, the Company cannot predict the outcome of the above matters.
	An unfavorable outcome on the Avid matters or the FastVDO matter referenced above or any other litigation matter could require that Harmonic pay substantial damages, or, in connection with any intellectual property infringement claims, could require that the Company pay ongoing royalty payments or could prevent the Company from selling certain of its products. As a result, a settlement of, or an unfavorable outcome on, any of such matters could have a material adverse effect on Harmonic’s business, operating results, financial position and cash flows.
	Harmonic’s industry is characterized by the existence of a large number of patents and frequent claims and related litigation regarding patent and other intellectual property rights. From time to time, third parties have asserted, and may in the future assert, exclusive patent, copyright, trademark and other intellectual property rights against us or the Company’s customers. Such assertions arise in the normal course of the Company’s operations. The resolution of any such assertions and claims cannot be predicted with certainty.

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 27, 2013
Equity [Abstract]	'
Stockholders' Equity	'
	STOCKHOLDERS’ EQUITY
	Accumulated Other Comprehensive Loss
	The components of accumulated other comprehensive loss were as follows (in thousands):
		27-Sep-13			31-Dec-12
	Foreign currency translation adjustments	$	(510	)	$	(502	)
	Unrealized gain on investments	43			37
	Accumulated other comprehensive loss	$	(467	)	$	(465	)
	Common Stock Repurchases
	On January 28, 2013, our Board of Directors approved a $75 million increase to our existing $25 million stock repurchase program. On February 19, 2013, the Board approved a further $35 million increase to the program upon the closing of a sale of the Company’s cable access HFC business, which closed on March 5, 2013. On July 16, 2013, the Board authorized repurchasing an additional $85.0 million under the Company’s stock repurchase program, increasing the aggregate authorized amount to $220 million under the ongoing program. Under the program, the Company is authorized to repurchase shares of common stock in open market transactions or pursuant to any trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The timing and actual number of shares repurchased, if any, depends on a variety of factors, including the price and availability of our shares, trading volume and general market conditions. The program may be suspended or discontinued at any time without prior notice.
	During the three and nine months ended September 27, 2013, the Company repurchased and retired 1.1 million and 4.5 million shares of common stock for $7.7 million and $27.6 million, respectively, under this program. As part of the stock repurchase program, on May 24, 2013, the Company completed a “modified Dutch auction” tender offer and repurchased and retired an additional 12.0 million shares of its common stock at $6.25 per share. The total cost of the stock repurchase under the tender offer was approximately $76.0 million, including $1.0 million of fees and expenses. The Company charges the excess of cost over par value for the repurchase of its common stock to additional paid-in capital. As of September 27, 2013, approximately $125.2 million had been utilized to repurchase stock under the program, including under the Company's tender offer, which closed on May 24, 2013, and approximately $94.8 million was available for future purchases under the program.

Basis_of_Presentation_and_Sign1

Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 27, 2013
Discontinued Operations	'
	Discontinued Operations
	On March 5, 2013, the Company completed the sale of its cable access HFC business to Aurora Networks (“Aurora”) for $46.0 million in cash. The Condensed Consolidated Statements of Operations have been retrospectively adjusted to present the cable access HFC business as discontinued operations, as described in “Note 3, Discontinued Operations”. Unless noted otherwise, all discussions herein with respect to the Company’s unaudited condensed consolidated financial statements relate to the Company’s continuing operations.
Use of Estimates	'
	Use of Estimates
	The preparation of the condensed consolidated financial statements in conformity with U.S. 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 2 to its audited Consolidated Financial Statements included in its 2012 Form 10-K. There have been no significant changes to these policies during the nine months ended September 27, 2013.
Reclassifications	'
	Reclassifications
	From time to time the Company reclassifies certain prior period balances to conform to the current year presentation. These reclassifications have no material impact on previously reported total assets, total liabilities, stockholders’ equity, results of operations or cash flows.
Recent Accounting Pronouncements	'
	RECENT ACCOUNTING PRONOUNCEMENTS
	In December 2011, the FASB issued Accounting Standard Update (“ASU”) 2011-11, “Disclosures about offsetting assets and liabilities”. This guidance enhances disclosure requirements about the nature of an entity’s right to offset. The new guidance requires the disclosure of the gross amounts subject to rights of set-off, amounts offset in accordance with the accounting standards followed, and the related net exposure. The new guidance became effective for the Company beginning in the first quarter of fiscal 2013 and it did not have any impact on the Company’s Consolidated Financial Statements.
	In July 2012, the FASB issued ASU 2012-2, “Intangibles - Goodwill and Other”, which allows an entity to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived asset is impaired for determining whether it is necessary to perform the quantitative impairment test. This accounting standard update became effective for the Company beginning in the first quarter of fiscal 2013 and did not have any impact on the Company’s Consolidated Financial Statements.
	In February 2013, the FASB issued ASU 2013-2, “Comprehensive Income”, which requires reclassification adjustments from other comprehensive income to be presented either in the financial statements or in the notes to the financial statements. The Company adopted this new guidance in the first quarter of fiscal 2013 and included the required disclosures.
	In March 2013, the FASB issued ASU 2013-4, “Obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date”. The update provides requirements for the recognition, measurement and disclosure of an entity’s reasonable expectation of its obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date. This guidance requires an entity to disclose the nature and amount of any such obligation, as well as other information about the obligation. The Company does not expect the adoption of ASU 2013-04 will have a material impact on its financial position, results of operations or cash flows. The guidance is effective for the Company beginning in the first quarter of its 2014 fiscal year and should be applied prospectively.
	In March 2013, the FASB issued ASU 2013-05, “Parent’s Accounting for the Cumulative Translation Adjustment upon De-recognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity”. The ASU addresses accounting for a cumulative translation adjustment when a parent either sells a part or all of its investment in a foreign entity or no longer holds a controlling financial interest in a subsidiary or group of assets that is a nonprofit activity or a business within a foreign entity. The guidance is effective for the Company beginning in the first quarter of its 2014 fiscal year and should be applied prospectively. The Company does not expect the adoption of ASU 2013-05 will have a material impact on its financial position, results of operations or cash flows.
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists”. Under certain circumstances, unrecognized tax benefits should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. The guidance is effective for the Company beginning in the first quarter of 2014. The Company is currently evaluating the impact this guidance may have on its financial position, results of operations and cash flows.
Impairment of Investments	'
	Impairment of Investments
	The Company monitors its investment portfolio for impairment on a periodic basis. In the event that the carrying value of an investment exceeds its fair value and the decline in value is determined to be other-than-temporary, an impairment charge is recorded and a new cost basis for the investment is established. A decline of fair value below amortized costs of debt securities is considered other-than-temporary if the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security before recovery of the entire amortized cost basis. At the present time, the Company does not intend to sell its investments that have unrealized losses in accumulated other comprehensive loss. In addition, the Company does not believe that it is more likely than not that it will be required to sell its investments that have unrealized losses in accumulated other comprehensive loss before the Company recovers the principal amounts invested. The Company believes that the unrealized losses are temporary and do not require an other-than-temporary impairment, based on its evaluation of available evidence as of September 27, 2013.
	As of September 27, 2013, there were no individual available-for-sale securities in a material unrealized loss position and the amount of unrealized losses on the total investment balance was insignificant.
Fair Value of Financial Instruments	'
	Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The guidance describes three levels of inputs that may be used to measure fair value:
	•	Level 1 — Observable inputs that reflect quoted prices for identical assets or liabilities in active markets.
	•	Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company primarily uses broker quotes for valuation of its short-term investments. The forward exchange contracts are classified as Level 2 because they are valued using quoted market prices and other observable data for similar instruments in an active market.
	•	Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	The Company uses the market approach to measure fair value for its financial assets and liabilities. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. During the nine months ended September 27, 2013, there were no nonrecurring fair value measurements of assets and liabilities subsequent to initial recognition.
Share-based Compensation Expense	'
	The Company estimated the fair value of all employee stock options using a Black-Scholes valuation model with the following weighted average assumptions:
		Three months ended				Nine months ended
		September 27,		September 28,		September 27,		September 28,
		2013		2012		2013		2012
	Expected term (years)	4.7		4.7		4.7		4.7
	Volatility	46	%	54	%	51	%	56	%
	Risk-free interest rate	1.5	%	0.7	%	0.8	%	0.9	%
	Expected dividends	0	%	0	%	0	%	0	%
	The expected term represents the weighted-average period that the stock options are expected to remain outstanding. The computation of the expected term was determined based on historical experience of similar awards, giving consideration to the contractual terms of the stock-based awards, vesting schedules and expectations of future employee behavior. The Company uses its historical volatility for a period equivalent to the expected term of the options to estimate the expected volatility. The risk-free interest rate that the Company uses in the Black-Scholes option valuation model is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation model.
	The Company is required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and records stock-based compensation expense only for those awards that are expected to vest. All stock-based payment awards are amortized on a straight-line basis over the requisite service periods of the awards, which are generally the vesting periods.
	The weighted-average fair value per share of options granted was $3.02 and $1.89 for the three months ended September 27, 2013 and September 28, 2012, respectively. The weighted-average fair value per share of options granted was $2.51 and $2.66 for the nine months ended September 27, 2013 and September 28, 2012, respectively.
	The fair value of all stock options vested during the three months ended September 27, 2013 and September 28, 2012 was $0.8 million and $0.8 million, respectively. The fair value of all stock options vested during the nine months ended September 27, 2013 and September 28, 2012 was $2.8 million and $3.8 million, respectively.
	The total realized tax benefit attributable to stock options exercised during the nine months ended September 28, 2012, in jurisdictions where this expense is deductible for tax purposes, was $80,000. The Company did not recognize any tax benefit attributable to stock options exercised during the nine months ended September 27, 2013.
	Restricted Stock Units
	The estimated fair value of restricted stock units is based on the market price of the Company’s common stock on the grant date. The fair value of all restricted stock units issued during the three months ended September 27, 2013 and September 28, 2012 was $2.8 million and $2.6 million, respectively. The fair value of all restricted stock units issued during the nine months ended September 27, 2013 and September 28, 2012 was $10.2 million and $10.3 million, respectively.
	Employee Stock Purchase Plan
	The value of the stock purchase rights under the ESPP consists of: (1) the 15% discount on the purchase of the stock; (2) 85% of the fair value of the call option; and (3) 15% of the fair value of the put option. The call option and put option were valued using the Black-Scholes option pricing model with the following assumptions:
		Purchase Period Ending		Purchase Period Ending
		June 30,		June 30,		December 31,
		2013		2012		2012
	Expected term (years)	0.49		0.5		0.5
	Volatility	30	%	53	%	46	%
	Risk-free interest rate	0.2	%	0.2	%	0.2	%
	Expected dividends	0	%	0	%	0	%
	The expected term represents the period of time from the beginning of the offering period to the purchase date. The Company uses its historical volatility for a period equivalent to the expected term of the options to estimate the expected volatility. The risk-free interest rate that the Company uses in the Black-Scholes option valuation model is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, used an expected dividend yield of zero in the valuation model.
	The fair value per share of stock purchase rights under the ESPP granted for the purchase period ended June 30, 2013 and June 30, 2012, was $1.23 and $1.51, respectively. The fair value per share of stock purchase rights under the ESPP granted for the purchase period ended December 31, 2012 was $1.19. The ESPP is suspended for the second half of 2013 due to all authorized shares under the plan having been issued through the offering period ended June 30, 2013. The Company’s stockholders approved a 1,000,000 share increase in the authorized shares for the ESPP during the Company’s annual meeting on August 14, 2013, and contributions under the ESPP will resume in January 2014. As a result, the Company will not have any stock-based compensation expense in the second half of fiscal 2013 related to the ESPP.
	Unrecognized Stock-Based Compensation
	As of September 27, 2013, total unamortized stock-based compensation cost related to unvested stock options and restricted stock units was $20.7 million. This amount will be recognized as expense using the straight-line attribution method over the remaining weighted-average amortization period of 2.0 years.
Income Tax	'
	The income tax provision includes federal, state and local and foreign income taxes and is based on the application of a forecasted annual income tax rate applied to the current quarter’s year-to-date pre-tax income (loss). In determining the estimated annual effective income tax rate, the Company estimates the annual impact of certain factors, including projections of the Company’s annual earnings, taxing jurisdictions in which the earnings will be generated, state and local income taxes, the Company’s ability to use tax credits and net operating loss carryforwards, and available tax planning alternatives. Discrete items, including the effect of changes in tax laws, tax rates, and certain circumstances with respect to valuation allowances or other unusual or non-recurring tax adjustments, are reflected in the period in which they occur as an addition to, or reduction from, the income tax provision, rather than being included in the estimated annual effective income tax rate.
	In compliance with applicable guidance for accounting for uncertainty in income taxes, the Company had gross unrecognized tax benefits, which include interest and penalties, of approximately $59.2 million as of December 31, 2012, and approximately $22.3 million as of September 27, 2013. If all of the unrecognized tax benefits at September 27, 2013 were recognized, the entire amount would impact the provision for income taxes. The unrecognized tax benefits may decrease significantly within the next 12 months if a related statute of limitations that is currently set to expire during that period is not extended.
	The realization of our deferred tax assets is dependent upon the generation of sufficient U.S and foreign taxable income in the future to offset against those assets. We may not have sufficient taxable income in the future to determine that we will be able to realize some significant portion of our deferred tax assets. As a result, an additional valuation allowance against our deferred tax assets may be required in the period in which such a determination is made, and our operating results could be materially and adversely impacted in the period of adjustment.
	The Company recognizes interest and possible penalties related to uncertain tax positions in income tax expense. During the nine months ended September 27, 2013, as a result of the expiration of the applicable statutes of limitations in the U.S. for 2008 and 2009 and in foreign jurisdictions for various years, the Company recorded a net decrease of $5.8 million for interest and possible penalties related to uncertain tax positions, resulting in a balance at September 27, 2013 of $1.4 million
Discontinued Operations [Member]	'
Discontinued Operations	'
	In accordance with ASC 205 “Presentation of financial statements – Discontinued Operations”, a business is classified as a discontinued operation when: (i) the operations and cash flows of the business can be clearly distinguished and have been or will be eliminated from our ongoing operations; (ii) the business has either been disposed of or is classified as held for sale; and (iii) the Company will not have any significant continuing involvement in the operations of the business after the disposal transactions.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 27, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Schedule of Details on Income Statement Caption on TSA Billing	'
	The table below provides details on the income statement caption under which the TSA billing was recorded (in thousands):
		Three months ended			Nine months ended
		27-Sep-13
	Product cost of revenue	$	41		$	577
	Research and development	—			21
	Selling, general and administrative	7			379
	Total TSA billing to Aurora	$	48		$	977
Recorded Gain With the Sale of Cable Access HFC Business	'
	The Company recorded a gain of $14.8 million for the nine months ended September 27, 2013, in connection with the sale of the cable access HFC business, calculated as follows (in thousands):
	Gross Proceeds				$	46,000
	Less : Carrying value of net assets
	Inventories, net	$	10,579
	Prepaid expenses and other current assets	612
	Property and equipment, net	1,180
	Goodwill de-recognized	14,547
	Deferred revenue	(4,499		)
	Accrued liabilities	(939		)
	Total net assets sold and de-recognized				$	21,480
	Less : Selling cost				$	2,473
	Less : Tax effect				$	7,234
	Gain on disposal, net of taxes				$	14,813
Revenues and Components of Net Income Related to Discontinued Operations	'
	Revenue and the components of net income related to the discontinued operations for the three and nine months ended September 27, 2013 and September 28, 2012 were as follows:
		Three months ended						Nine months ended
		27-Sep-13			28-Sep-12			27-Sep-13			28-Sep-12
	Revenue	$	161		$	16,291		$	9,717		$	38,147
	Operating income	$	154		$	3,070		$	669		$	5,193
	Less : provision for (benefit from) income taxes	57			6,831			(137		)	3,855
	Add : Gain (loss) on disposal, net of taxes	(6		)	—			14,813			—
	Income (loss) from discontinued operations, net of taxes	$	91		$	(3,761	)	$	15,619		$	1,338

ShortTerm_Investments_Tables

Short-Term Investments (Tables)	9 Months Ended
	Sep. 27, 2013
Cash and Cash Equivalents [Abstract]	'
Summary of Short-Term Investments	'
	The following table summarizes the Company’s short-term investments (in thousands):
		Amortized		Gross		Gross			Estimated
		Cost		Unrealized		Unrealized			Fair Value
				Gains		Losses
	As of September 27, 2013
	State, municipal and local government agencies bonds	$	36,195	$	41	$	(3	)	$	36,233
	Corporate bonds	32,376		16		(11		)	32,381
	Commercial paper	3,348		—		—			3,348
	U.S. federal government bonds	4,001		3		—			4,004
	Total short-term investments	$	75,920	$	60	$	(14	)	$	75,966
	As of December 31, 2012
	Certificates of deposit	$	1,603	$	—	$	—		$	1,603
	State, municipal and local government agencies bonds	59,009		45		(4		)	59,050
	Corporate bonds	31,568		4		(10		)	31,562
	Commercial paper	10,287		1		—			10,288
	U.S. federal government bonds	2,003		—		—			2,003
	Total short-term investments	$	104,470	$	50	$	(14	)	$	104,506
Maturities of Short-Term Investments	'
	The following table summarizes the maturities of the Company’s short-term investments (in thousands):
		27-Sep-13		31-Dec-12
	Less than one year	$	50,782	$	76,779
	Due in 1 - 2 years	25,184		27,727
	Total short-term investments	$	75,966	$	104,506

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 27, 2013
Fair Value Disclosures [Abstract]	'
Financial Assets and Liabilities Measured at Fair Value Based on Three-Tier Fair Value Hierarchy	'
	The following table sets forth the fair value of the Company’s financial assets and liabilities measured at fair value based on the three-tier fair value hierarchy (in thousands):
		Level 1		Level 2		Level 3		Total
	As of September 27, 2013
	Cash equivalents
	Money market funds	$	58,220	$	—	$	—	$	58,220
	Short-term investments
	State, municipal and local government agencies bonds	—		36,233		—		36,233
	Corporate bonds	—		32,381		—		32,381
	Commercial paper	—		3,348		—		3,348
	U.S. federal government bonds	4,004		—		—		4,004
	Prepaids and other current assets
	Foreign exchange forward contracts	—		5		—		5
	Total assets measured and recorded at fair value	$	62,224	$	71,967	$	—	$	134,191
	Accrued liabilities
	Foreign exchange forward contracts	$	—	$	381	$	—	$	381
	Total liabilities measured and recorded at fair value	$	—	$	381	$	—	$	381
		Level 1		Level 2		Level 3		Total
	As of December 31, 2012
	Cash equivalents
	Money market funds	$	54,923	$	—	$	—	$	54,923
	Corporate bonds with maturity less than 90 days	—		3,614		—		3,614
	U.S. federal government bonds with maturity less than 90 days	3,005		—		—		3,005
	Short-term investments
	Certificates of deposit	—		1,603		—		1,603
	State, municipal and local government agencies bonds	—		59,050		—		59,050
	Corporate bonds	—		31,562		—		31,562
	Commercial paper	—		10,288		—		10,288
	U.S. federal government bonds	2,003		—		—		2,003
	Prepaids and other current assets
	Foreign exchange forward contracts	—		344		—		344
	Total assets measured and recorded at fair value	$	59,931	$	106,461	$	—	$	166,392
	Accrued liabilities
	Foreign exchange forward contracts	$	—	$	143	$	—	$	143
	Total liabilities measured and recorded at fair value	$	—	$	143	$	—	$	143

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 27, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Accounts Receivable, Net	'
		27-Sep-13			31-Dec-12
	Accounts receivable, net:
	Accounts receivable	$	94,283		$	95,515
	Less: allowances for doubtful accounts, returns and discounts	(9,214		)	(9,595		)
	Accounts receivable, net	$	85,069		$	85,920
Inventories	'
	Inventories:
	Raw materials	$	3,188		$	10,731
	Work-in-process	1,378			4,347
	Finished goods	35,803			49,192
	Total inventories	$	40,369		$	64,270
Property and Equipment, Net	'
	Property and equipment, net:
	Furniture and fixtures	$	8,104		$	7,856
	Machinery and equipment	111,182			108,262
	Leasehold improvements	7,686			7,612
	Property and equipment, gross	126,972			123,730
	Less: accumulated depreciation and amortization	(91,421		)	(85,608		)
	Property and equipment, net	$	35,551		$	38,122

Goodwill_and_Identified_Intang1

Goodwill and Identified Intangible Assets (Tables)	9 Months Ended
	Sep. 27, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Changes in Carrying Amount of Goodwill	'
	The changes in the carrying amount of goodwill for the nine months ended September 27, 2013 are as follows (in thousands):
	Balance at beginning of period	$	212,518
	Reduction in goodwill associated with the sale of the cable access HFC Business	(14,547		)
	Foreign currency translation adjustment	(15		)
	Balance at end of period	$	197,956
Summary of Goodwill and Identified Intangible Assets	'
	The following is a summary of identified intangible assets (in thousands):
		27-Sep-13								31-Dec-12
		Gross Carrying			Accumulated			Net Carrying		Gross Carrying		Accumulated			Net Carrying
		Amount			Amortization			Amount		Amount		Amortization			Amount
	Identifiable intangibles:
	Developed core technology	$	136,145		$	(116,918	)	$	19,227	$	136,145	$	(102,449	)	$	33,696
	Customer relationships/contracts	67,098			(52,381		)	14,717		67,098		(48,150		)	18,948
	Trademarks and tradenames	11,361			(10,210		)	1,151		11,361		(9,145		)	2,216
	Maintenance agreements and related relationships	7,100			(4,317		)	2,783		7,100		(3,513		)	3,587
	Total identifiable intangibles	$	221,704		$	(183,826	)	$	37,878	$	221,704	$	(163,257	)	$	58,447
Amortization Expense for Identifiable Purchased Intangible Assets	'
	Amortization expense for the identifiable purchased intangible assets for the three and nine months ended September 27, 2013 and September 28, 2012 was allocated as follows (in thousands):
		Three months ended						Nine months ended
		September 27,			September 28,			September 27,		September 28,
		2013			2012			2013		2012
	Included in cost of revenue	$	4,763		$	5,048		$	14,470	$	15,456
	Included in operating expenses	2,001			2,179			6,099		6,548
	Total amortization expense	$	6,764		$	7,227		$	20,569	$	22,004
Estimated Future Amortization Expense of Purchased Intangible Assets	'
	The estimated future amortization expense of purchased intangible assets with definite lives is as follows (in thousands):
		Cost of Revenue			Operating			Total
					Expenses
	Year ended December 31,
	2013 (remaining 3 months)	$	4,763		$	1,997		$	6,760
	2014	13,745			6,775			20,520
	2015	719			5,783			6,502
	2016	—			4,096			4,096
	2017	—			—			—
	Total future amortization expense	$	19,227		$	18,651		$	37,878

Restructuring_and_Related_Char1

Restructuring and Related Charges (Tables)	9 Months Ended
	Sep. 27, 2013
Omneon Restructuring [Member]	'
Activities in Restructuring Accrual	'
	The following table summarizes the activity in the Omneon restructuring accrual during the nine months ended September 27, 2013 (in thousands):
		Excess
		Facilities
	Balance at December 31, 2012	$	869
	Cash payments	(897		)
	Accretion	28
	Balance at September 27, 2013	—
HFC business [Member]	'
Activities in Restructuring Accrual	'
	The following table summarizes the activity in the HFC restructuring accrual during the nine months ended September 27, 2013 (in thousands):
		Severance			Contract			Total
					Termination
	Balance at December 31, 2012	$	—		$	—		$	—
	Restructuring charges in discontinued operations	403			124			527
	Adjustments to restructuring provisions	119			(29		)	90
	Cash payments	(492		)	(95		)	(587		)
	Balance at September 27, 2013	30			—			30
Harmonic 2013 Restructuring [Member]	'
Activities in Restructuring Accrual	'
	The following table summarizes the activity in the Harmonic 2013 restructuring accrual during the nine months ended September 27, 2013 (in thousands):
		Severance			Impairment			Obsolete inventories			Total
					of Leasehold
					Improvement
	Balance at December 31, 2012	$	—		$	—		$	—		$	—
	Restructuring charges in continuing operations	1,089			101			151			1,341
	Adjustments to restructuring provisions	66			48			—			114
	Cash payments	(1,060		)	—			—			(1,060		)
	Non-cash write-offs	—			(149		)	(151		)	(300		)
	Balance at September 27, 2013	95			—			—			95

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 27, 2013
Postemployment Benefits [Abstract]	'
Summary of Company's Stock Option and Restricted Stock Unit Activity	'
	The following table summarizes the Company’s stock option and RSU unit activity during the nine months ended September 27, 2013 (in thousands, except per share amounts):
				Stock Options Outstanding						Restricted Stock Units Outstanding
		Shares		Number			Weighted			Number		Weighted
		Available for		of			Average			of		Average
		Grant		Shares			Exercise Price			Units		Grant
												Date Fair
												Value
	Balance at December 31, 2012	10,155		8,900			$	6.83		3,938		$	6.44
	Authorized	—		—			—			—		—
	Granted	(3,361	)	1,360			5.81			1,333		5.84
	Options exercised	—		(788	)		4.15			—		—
	Shares released	—		—			—			(1,622	)	6.28
	Forfeited or cancelled	2,015		(1,461	)		6.92			(418	)	6.51
	Balance at September 27, 2013	8,809		8,011			$	6.9		3,231		$	6.27
Summary of Stock Options Outstanding	'
	The following table summarizes information about stock options outstanding as of September 27, 2013 (in thousands, except per share amounts):
		Number		Weighted				Weighted	Aggregate
		of		Average				Average	Intrinsic
		Shares		Exercise				Remaining	Value
				Price				Contractual
								Term (Years)
	Vested and expected to vest	7,719		$	6.94			3.3	$	9,532
	Exercisable	5,604		7.27				2.3	5,516
Summary of Restricted Stock Units Outstanding	'
	The following table summarizes information about restricted stock units outstanding as of September 27, 2013 (in thousands, except per share amounts):
		Number of		Weighted		Aggregate
		Shares		Average		Fair
		Underlying		Remaining		Value (1)
		Restricted		Vesting
		Stock		Period
		Units		(Years)
	Vested and expected to vest	2,934		0.9		$	22,824
	-1	Represents the fair value of the Company’s common stock as of September 27, 2013, times the number of restricted stock units vested and expected to vest as of the same date.

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 27, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of Stock-Based Compensation Expense	'
	The following table summarizes stock-based compensation expense (in thousands):
		Three months ended							Nine months ended
		September 27,			September 28,				September 27,			September 28,
		2013			2012				2013			2012
	Stock-based compensation in:
	Cost of revenue	$	605		$	659			$	1,838		$	2,176
	Research and development expense	1,076			1,450				3,400			4,755
	Selling, general and administrative expense	2,264			2,388				6,628			6,816
	Total stock-based compensation in operating expense	3,340			3,838				10,028			11,571
	Total stock-based compensation	$	3,945		$	4,497			$	11,866		$	13,747
Valuation Assumptions for Stock Options	'
	The Company estimated the fair value of all employee stock options using a Black-Scholes valuation model with the following weighted average assumptions:
		Three months ended					Nine months ended
		September 27,		September 28,			September 27,			September 28,
		2013		2012			2013			2012
	Expected term (years)	4.7		4.7			4.7			4.7
	Volatility	46	%	54	%		51	%		56	%
	Risk-free interest rate	1.5	%	0.7	%		0.8	%		0.9	%
	Expected dividends	0	%	0	%		0	%		0	%
Employee Stock Purchase Plan	'
	The call option and put option were valued using the Black-Scholes option pricing model with the following assumptions:
		Purchase Period Ending		Purchase Period Ending
		June 30,		June 30,			December 31,
		2013		2012			2012
	Expected term (years)	0.49		0.5			0.5
	Volatility	30	%	53	%		46	%
	Risk-free interest rate	0.2	%	0.2	%		0.2	%
	Expected dividends	0	%	0	%		0	%

Income_Loss_Per_Share_Tables

Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 27, 2013
Earnings Per Share [Abstract]	'
Numerators and Denominators of Basic and Diluted Net Income (Loss) Per Share Computations	'
	The following table sets forth the computation of the basic and diluted net loss per share (in thousands, except per share amounts):
		Three months ended						Nine months ended
		September 27,			September 28,			September 27,		September 28,
		2013			2012			2013		2012
	Numerator:
	Income (loss) from continuing operations	$	36,675		$	(4,469	)	$	23,768	$	(17,079	)
	Income (loss) from discontinued operations	91			(3,761		)	15,619		1,338
	Net income (loss)	$	36,766		$	(8,230	)	$	39,387	$	(15,741	)
	Denominator:
	Weighted average number of common shares outstanding
	Basic	101,144			116,517			108,695		116,946
	Effect of dilutive securities from stock options, restricted stock units and ESPP	1,579			—			1,184		—
	Diluted	102,723			116,517			109,879		116,946
	Basic net income (loss) per share from:
	Continuing operations	$	0.36		$	(0.04	)	$	0.22	$	(0.15	)
	Discontinued operations	$	—		(0.03		)	0.14		0.01
	Net Income (loss)	$	0.36		$	(0.07	)	$	0.36	$	(0.13	)
	Diluted net income (loss) per share from:
	Continuing operations	$	0.36		$	(0.04	)	$	0.22	$	(0.15	)
	Discontinued operations	$	—		$	(0.03	)	$	0.14	$	0.01
	Net Income (loss)	$	0.36		$	(0.07	)	$	0.36	$	(0.13	)
Anti-dilutive Securities	'
	The following table sets forth the potentially dilutive shares from stock options, restricted stock units and the ESPP, for the periods presented, that were excluded from the net income (loss) per share computations because their effect was anti-dilutive (in thousands):
		Three months ended					Nine months ended
		September 27,		September 28,			September 27,		September 28,
		2013		2012			2013		2012
	Potentially dilutive equity awards outstanding	6,144		13,608			10,447		13,382

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 27, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Future Minimum Lease Payments Under Non-cancelable Operating Leases	'
	Future minimum lease payments under non-cancelable operating leases as of September 27, 2013, after giving effect to $0.5 million of future sublease income from Aurora, are as follows (in thousands):
	Years ending December 31,
	2013 (remaining three months)	$	2,645
	2014	9,600
	2015	9,047
	2016	7,811
	2017	7,659
	Thereafter	21,157
	Total	$	57,919
Summary of Warranty Accrual Included in Accrued Liabilities	'
	Activity for the Company’s warranty accrual, which is included in accrued liabilities, is summarized below (in thousands):
		Three months ended						Nine months ended
		September 27,			September 28,			September 27,			September 28,
		2013			2012			2013			2012
	Balance at beginning of period	$	3,228		$	4,725		$	4,292		$	5,558
	Transfer to Aurora as part of the sale of discontinued operations	—			—			(939		)	—
	Accrual for current period warranties	1,991			1,314			5,333			4,407
	Warranty costs incurred	(1,705		)	(1,677		)	(5,172		)	(5,603		)
	Balance at end of period	$	3,514		$	4,362		$	3,514		$	4,362

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 27, 2013
Equity [Abstract]	'
Components of Accumulated Other Comprehensive Loss	'
	The components of accumulated other comprehensive loss were as follows (in thousands):
		27-Sep-13			31-Dec-12
	Foreign currency translation adjustments	$	(510	)	$	(502	)
	Unrealized gain on investments	43			37
	Accumulated other comprehensive loss	$	(467	)	$	(465	)

Basis_of_Presentation_and_Sign2

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) (HFC business [Member], USD $)	1 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Mar. 05, 2013	Sep. 27, 2013
HFC business [Member]	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Business sold for cash agreed by the company	$46,000	$46,000

Discontinued_Operations_Additi

Discontinued Operations - Additional Information (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012	Mar. 05, 2013	Mar. 05, 2013	Mar. 29, 2013	Sep. 27, 2013	Sep. 27, 2013	Sep. 27, 2013	Mar. 05, 2013	Mar. 29, 2013	Jun. 28, 2013
			Contract Manufacturing [Member]	Other Product Manufacturing Support Services [Member]	HFC business [Member]	HFC business [Member]	Aurora [Member]	Aurora [Member]	Aurora [Member]	Aurora [Member]	Aurora [Member]
									HFC business [Member]	HFC business [Member]	HFC business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Gross proceeds from sale of cable access HFC business	'	'	'	'	'	$46,000,000	'	'	$46,000,000	'	'
Net gain from sale of HFC business	'	'	'	'	'	'	'	'	'	15,000,000	14,800,000
Transition services agreement, term	'	'	'5 months	'2 months	'	'	'	'	'	'	'
Adjustments on inventory and fixed assets	'	'	'	'	'	'	'	'	'	'	-200,000
Total TSA billing to Aurora	'	'	'	'	'	'	48,000	977,000	'	'	'
Prepaid expenses and other current assets	14,757,000	23,636,000	'	'	'	'	0	0	'	'	'
Receivables from customers	'	'	'	'	'	'	200,000	200,000	'	'	'
Accrued liabilities	'	'	'	'	'	'	200,000	200,000	'	'	'
Payable to third party vendors for purchases	'	'	'	'	'	'	0	0	'	'	'
Goodwill impairment loss	'	'	'	'	0	'	'	'	'	'	'
Carrying value of goodwill based on the fair value	$14,547,000	'	'	'	$14,547,000	$14,547,000	'	'	'	'	'

Discontinued_Operations_Schedu

Discontinued Operations - Schedule of Details on Income Statement Caption on TSA Billing (Detail) (Aurora [Member], USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 27, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Total TSA billing to Aurora	$48	$977
Product cost of revenue [Member]	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Total TSA billing to Aurora	41	577
Research and development expense [Member]	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Total TSA billing to Aurora	0	21
Selling, general and administrative expenses [Member]	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Total TSA billing to Aurora	$7	$379

Discontinued_Operations_Record

Discontinued Operations - Recorded Gain With the Sale of Cable Access HFC Business (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012	Mar. 29, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Goodwill de-recognized	$14,547	'	$14,547	'	'
Gain on disposal, net of taxes	'	'	14,813	0	'
HFC business [Member]	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Gross Proceeds	'	'	46,000	'	'
Inventories, net	10,579	'	10,579	'	'
Prepaid expenses and other current assets	612	'	612	'	'
Property and equipment, net	1,180	'	1,180	'	'
Goodwill de-recognized	14,547	'	14,547	'	14,547
Deferred revenue	-4,499	'	-4,499	'	'
Accrued liabilities	-939	'	-939	'	'
Total net assets sold and de-recognized	21,480	'	21,480	'	'
Less : Selling cost	'	'	2,473	'	'
Less : Tax effect	'	'	7,234	'	'
Gain on disposal, net of taxes	($6)	$0	$14,813	$0	'

Discontinued_Operations_Revenu

Discontinued Operations - Revenues and Components of Net Income Related to Discontinued Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Add: Gain (loss) on disposal, net of taxes	'	'	$14,813	$0
Income (loss) from discontinued operations, net of taxes	91	-3,761	15,619	1,338
HFC business [Member]	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Revenue	161	16,291	9,717	38,147
Operating income	154	3,070	669	5,193
Less : provision for (benefit from) income taxes	57	6,831	-137	3,855
Add: Gain (loss) on disposal, net of taxes	-6	0	14,813	0
Income (loss) from discontinued operations, net of taxes	$91	($3,761)	$15,619	$1,338

ShortTerm_Investments_Summary_

Short-Term Investments - Summary of Short-Term Investments (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized Cost	$75,920	$104,470
Gross Unrealized Gains	60	50
Gross Unrealized Losses	-14	-14
Total short-term investments, Estimated Fair Value	75,966	104,506
Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized Cost	'	1,603
Gross Unrealized Gains	'	0
Gross Unrealized Losses	'	0
Total short-term investments, Estimated Fair Value	'	1,603
State, municipal and local government agencies bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized Cost	36,195	59,009
Gross Unrealized Gains	41	45
Gross Unrealized Losses	-3	-4
Total short-term investments, Estimated Fair Value	36,233	59,050
Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized Cost	32,376	31,568
Gross Unrealized Gains	16	4
Gross Unrealized Losses	-11	-10
Total short-term investments, Estimated Fair Value	32,381	31,562
Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized Cost	3,348	10,287
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Total short-term investments, Estimated Fair Value	3,348	10,288
U.S. federal government bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Amortized Cost	4,001	2,003
Gross Unrealized Gains	3	0
Gross Unrealized Losses	0	0
Total short-term investments, Estimated Fair Value	$4,004	$2,003

ShortTerm_Investments_Maturiti

Short-Term Investments - Maturities of Short-Term Investments (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Less than one year	$50,782	$76,779
Due in 1 - 2 years	25,184	27,727
Total short-term investments, Estimated Fair Value	$75,966	$104,506

ShortTerm_Investments_Addition

Short-Term Investments - Additional Information (Detail) (USD $)	Sep. 27, 2013
Investments, Debt and Equity Securities [Abstract]	'
Available-for-sale securities in a material unrealized loss position	$0

Fair_Value_Measurements_Financ

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value Based on Three-Tier Fair Value Hierarchy (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	$62,224	$59,931
Total liabilities measured and recorded at fair value	0	0
Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	71,967	106,461
Total liabilities measured and recorded at fair value	381	143
Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Total liabilities measured and recorded at fair value	0	0
Estimate of Fair Value Measurement [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	134,191	166,392
Total liabilities measured and recorded at fair value	381	143
Cash equivalents [Member] | Level 1 [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	58,220	54,923
Cash equivalents [Member] | Level 1 [Member] | Corporate bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	0
Cash equivalents [Member] | Level 1 [Member] | U.S. federal government bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	3,005
Cash equivalents [Member] | Level 2 [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Cash equivalents [Member] | Level 2 [Member] | Corporate bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	3,614
Cash equivalents [Member] | Level 2 [Member] | U.S. federal government bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	0
Cash equivalents [Member] | Level 3 [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Cash equivalents [Member] | Level 3 [Member] | Corporate bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	0
Cash equivalents [Member] | Level 3 [Member] | U.S. federal government bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	0
Cash equivalents [Member] | Estimate of Fair Value Measurement [Member] | Money market funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	58,220	54,923
Cash equivalents [Member] | Estimate of Fair Value Measurement [Member] | Corporate bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	3,614
Cash equivalents [Member] | Estimate of Fair Value Measurement [Member] | U.S. federal government bonds [Member] | Maturity less than 90 days [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	3,005
Short-term investments [Member] | Level 1 [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	0
Short-term investments [Member] | Level 1 [Member] | State, municipal and local government agencies bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Level 1 [Member] | Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Level 1 [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Level 1 [Member] | U.S. federal government bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	4,004	2,003
Short-term investments [Member] | Level 2 [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	1,603
Short-term investments [Member] | Level 2 [Member] | State, municipal and local government agencies bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	36,233	59,050
Short-term investments [Member] | Level 2 [Member] | Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	32,381	31,562
Short-term investments [Member] | Level 2 [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	3,348	10,288
Short-term investments [Member] | Level 2 [Member] | U.S. federal government bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Level 3 [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	0
Short-term investments [Member] | Level 3 [Member] | State, municipal and local government agencies bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Level 3 [Member] | Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Level 3 [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Level 3 [Member] | U.S. federal government bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Short-term investments [Member] | Estimate of Fair Value Measurement [Member] | Certificates of deposit [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	'	1,603
Short-term investments [Member] | Estimate of Fair Value Measurement [Member] | State, municipal and local government agencies bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	36,233	59,050
Short-term investments [Member] | Estimate of Fair Value Measurement [Member] | Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	32,381	31,562
Short-term investments [Member] | Estimate of Fair Value Measurement [Member] | Commercial paper [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	3,348	10,288
Short-term investments [Member] | Estimate of Fair Value Measurement [Member] | U.S. federal government bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	4,004	2,003
Prepaids and other current assets [Member] | Level 1 [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Prepaids and other current assets [Member] | Level 2 [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	5	344
Prepaids and other current assets [Member] | Level 3 [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	0	0
Prepaids and other current assets [Member] | Estimate of Fair Value Measurement [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total assets measured and recorded at fair value	5	344
Accrued liabilities [Member] | Level 1 [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total liabilities measured and recorded at fair value	0	0
Accrued liabilities [Member] | Level 2 [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total liabilities measured and recorded at fair value	381	143
Accrued liabilities [Member] | Level 3 [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total liabilities measured and recorded at fair value	0	0
Accrued liabilities [Member] | Estimate of Fair Value Measurement [Member] | Foreign exchange forward contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Total liabilities measured and recorded at fair value	$381	$143

Balance_Sheet_Components_Accou

Balance Sheet Components - Accounts Receivable, Net, Inventories, Property and Equipment, Net (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Accounts receivable, net	'	'
Accounts receivable	$94,283	$95,515
Less: allowances for doubtful accounts, returns and discounts	-9,214	-9,595
Accounts receivable, net	85,069	85,920
Inventories:	'	'
Raw materials	3,188	10,731
Work-in-process	1,378	4,347
Finished goods	35,803	49,192
Total inventories, net	40,369	64,270
Property and equipment, net:	'	'
Furniture and fixtures	8,104	7,856
Machinery and equipment	111,182	108,262
Leasehold improvements	7,686	7,612
Property, Plant and Equipment Gross, Total	126,972	123,730
Less: accumulated depreciation and amortization	-91,421	-85,608
Property and equipment, net	$35,551	$38,122

Goodwill_and_Identified_Intang2

Goodwill and Identified Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Balance at beginning of period	$212,518
Reduction in goodwill associated with the sale of the cable access HFC Business	-14,547
Foreign currency translation adjustment	-15
Balance at end of period	$197,956

Goodwill_and_Identified_Intang3

Goodwill and Identified Intangible Assets - Summary of Goodwill and Identified Intangible Assets (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	$221,704	$221,704
Accumulated Amortization	-183,826	-163,257
Total	37,878	58,447
Developed core technology [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	136,145	136,145
Accumulated Amortization	-116,918	-102,449
Total	19,227	33,696
Customer relationships/contracts [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	67,098	67,098
Accumulated Amortization	-52,381	-48,150
Total	14,717	18,948
Trademarks and tradenames [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	11,361	11,361
Accumulated Amortization	-10,210	-9,145
Total	1,151	2,216
Maintenance agreements and related relationships [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	7,100	7,100
Accumulated Amortization	-4,317	-3,513
Total	$2,783	$3,587

Goodwill_and_Identified_Intang4

Goodwill and Identified Intangible Assets - Amortization Expense for Identifiable Purchased Intangible Assets (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Total amortization expense	$6,764	$7,227	$20,569	$22,004
Product cost of revenue [Member]	'	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Total amortization expense	4,763	5,048	14,470	15,456
Operating Expenses [Member]	'	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Total amortization expense	$2,001	$2,179	$6,099	$6,548

Goodwill_and_Identified_Intang5

Goodwill and Identified Intangible Assets - Estimated Future Amortization Expense of Purchased Intangible Assets (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
2013 (remaining 3 months)	$6,760	'
2014	20,520	'
2015	6,502	'
2016	4,096	'
2017	0	'
Total	37,878	58,447
Product cost of revenue [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
2013 (remaining 3 months)	4,763	'
2014	13,745	'
2015	719	'
2016	0	'
2017	0	'
Total	19,227	'
Operating Expenses [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
2013 (remaining 3 months)	1,997	'
2014	6,775	'
2015	5,783	'
2016	4,096	'
2017	0	'
Total	$18,651	'

Restructuring_and_Related_Char2

Restructuring and Related Charges - Activities in Restructuring Accrual (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013
Harmonic 2013 Restructuring [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	$0
Restructuring charges in continuing operations	1,341
Adjustments to restructuring provisions	114
Cash payments	-1,060
Non-cash write-offs	-300
Ending Balance	95
Harmonic 2013 Restructuring [Member] | Employee Severance And Benefit Arrangements [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	0
Restructuring charges in continuing operations	1,089
Adjustments to restructuring provisions	66
Cash payments	-1,060
Non-cash write-offs	0
Ending Balance	95
Harmonic 2013 Restructuring [Member] | Impairment of Leasehold improvement [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	0
Restructuring charges in continuing operations	101
Adjustments to restructuring provisions	48
Cash payments	0
Non-cash write-offs	-149
Ending Balance	0
Harmonic 2013 Restructuring [Member] | Obsolete Inventory [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	0
Restructuring charges in continuing operations	151
Adjustments to restructuring provisions	0
Cash payments	0
Non-cash write-offs	-151
Ending Balance	0
Omneon Restructuring [Member] | Excess Facilities [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	869
Cash payments	-897
Accretion	28
Ending Balance	0
HFC business [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	0
Restructuring charges in discontinued operations	527
Adjustments to restructuring provisions	90
Cash payments	-587
Ending Balance	30
HFC business [Member] | Employee Severance And Benefit Arrangements [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	0
Restructuring charges in discontinued operations	403
Adjustments to restructuring provisions	119
Cash payments	-492
Ending Balance	30
HFC business [Member] | Contract termination [Member]	'
Restructuring Cost and Reserve [Line Items]	'
Beginning Balance	0
Restructuring charges in discontinued operations	124
Adjustments to restructuring provisions	-29
Cash payments	-95
Ending Balance	$0

Restructuring_and_Related_Char3

Restructuring and Related Charges - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

In Thousands, unless otherwise specified

Sep. 27, 2013

Sep. 28, 2012

Sep. 27, 2013

Sep. 28, 2012

Sep. 27, 2013

Sep. 27, 2013

Dec. 31, 2012

Sep. 27, 2013

Dec. 31, 2012

Sep. 27, 2013

Dec. 31, 2012

Sep. 27, 2013

Sep. 27, 2013

Dec. 31, 2012

Sep. 27, 2013

Sep. 27, 2013

Sep. 27, 2013

Dec. 31, 2012

Sep. 27, 2013

Dec. 31, 2012

Sep. 27, 2013

Dec. 31, 2012

HFC business [Member]

HFC business [Member]

HFC business [Member]

HFC business [Member]

HFC business [Member]

HFC business [Member]

HFC business [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Harmonic 2013 Restructuring [Member]

Employee

Employee Severance And Benefit Arrangements [Member]

Employee Severance And Benefit Arrangements [Member]

Contract termination [Member]

Contract termination [Member]

Employee

Product cost of revenue [Member]

Operating expense [Member]

Employee Severance And Benefit Arrangements [Member]

Employee Severance And Benefit Arrangements [Member]

Leasehold Improvements [Member]

Leasehold Improvements [Member]

Obsolete Inventory [Member]

Obsolete Inventory [Member]

Restructuring Cost and Reserve [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discontinued Operation Restructuring Expense

'

'

'

'

$16

$617

'

$522

'

$95

'

'

'

'

'

'

'

'

'

'

'

'

Restructuring charges

259

0

925

0

'

'

'

'

'

'

'

600

1,500

'

530

925

1,200

'

'

'

'

'

Number of termination of employees

'

'

'

'

'

9

'

'

'

'

'

'

63

'

'

'

'

'

'

'

'

'

Number Of Employees Terminated Required to be Hired

'

'

'

'

'

10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of terminated employees required to work end of TSA Period

'

'

'

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restructuring Reserve

'

'

'

'

30

30

0

30

0

0

0

95

95

0

'

'

95

0

0

0

0

0

Non-cash write-offs

'

'

'

'

'

'

'

'

'

'

'

'

$300

'

'

'

$0

'

$149

'

$151

'

Credit_Facilities_Additional_I

Credit Facilities - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 27, 2013
Debt Instrument [Line Items]	'
Maximum borrowing capacity under bank line of credit facility	$10,000,000
Bank line of credit facility, maturity date	22-Aug-14
Amounts outstanding under bank line of credit facility	0
Borrowings under bank line of credit facility	0
Unrestricted cash, cash equivalents and short term investments to current liabilities ratio	'maintain a ratio of unrestricted cash, accounts receivable and short term investments to current liabilities (less deferred revenue) of at least 1.75 to 1.00.
Line of Credit Facility, Covenant, Unrestricted Cash, Accounts Receivable and Short Term Investments to Current Liabilities Less Deferred Revenue Ratio	1.75
Line of credit facility financial covenant terms	'4.71 to 1
Interest rate	3.25%
LIBOR rate duration	'one month borrowing period at September 27, 2013
Credit facility collateral	'Borrowings are not collateralized
Covenants under the line of credit facility	'As of September 27, 2013, Harmonic was in compliance with the covenants under the line of credit facility
Line of Credit Facility, Covenant Ratio, Ratio During Period	4.71
LIBOR [Member]	'
Debt Instrument [Line Items]	'
Annualized rate of LIBOR	0.18%
Standby letters of credit [Member]	'
Debt Instrument [Line Items]	'
Maximum borrowing capacity under bank line of credit facility	200,000
Line of credit facility [Member]	'
Debt Instrument [Line Items]	'
Maximum borrowing capacity under bank line of credit facility	$9,800,000
Minimum [Member] | LIBOR [Member]	'
Debt Instrument [Line Items]	'
Percentage added to LIBOR to facilitate line of credit	1.75%
Maximum [Member] | LIBOR [Member]	'
Debt Instrument [Line Items]	'
Percentage added to LIBOR to facilitate line of credit	1.93%

Employee_Benefit_Plans_Summary

Employee Benefit Plans - Summary of Company's Stock Option and Restricted Stock Unit Activity (Detail) (USD $)	9 Months Ended
	Sep. 27, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Shares Available for Grant, Beginning balance	10,155,000
Shares Available for Grant, Authorized	0
Shares Available for Grant, Granted	-3,361,000
Shares Available for Grant, Options exercised	0
Shares Available for Grant, Shares released	0
Shares Available for Grant, Forfeited or cancelled	2,015,000
Shares Available for Grant, Ending balance	8,809,000
Restricted Stock Units Outstanding [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of Units, Beginning balance	3,938,000
Number of Shares, Authorized	0
Number of Units, Granted	1,333,000
Number of Units, exercised	0
Number of Units, Shares released	-1,622,000
Number of Units, Forfeited or cancelled	-418,000
Number of Units, Ending balance	3,231,000
Weighted Average Grant Date Fair Value, Beginning balance	6.44
Weighted Average Grant Date Fair Value, Authorized	0
Weighted Average Grant Date Fair Value, Granted	5.84
Weighted Average Grant Date Fair Value, Exercised	0
Weighted Average Grant Date Fair Value, Shares released	6.28
Weighted Average Grant Date Fair Value, Forfeited or cancelled	6.51
Weighted Average Grant Date Fair Value, Ending balance	6.27
Stock Options Outstanding [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of Shares, Beginning balance	8,900,000
Number of Shares, Authorized	0
Number of Shares, Granted	1,360,000
Number of Shares, Options exercised	-788,000
Number of Shares, Forfeited or cancelled	-1,461,000
Number of Shares, Ending balance	8,011,000
Weighted Average Exercise Price, Beginning balance	6.83
Weighted Average Exercise Price, Authorized	0
Weighted Average Exercise Price, Granted	5.81
Weighted Average Exercise Price, Options exercised	4.15
Weighted Average Exercise Price, Forfeited or cancelled	6.92
Weighted Average Exercise Price, Ending balance	6.9

Employee_Benefit_Plans_Summary1

Employee Benefit Plans - Summary of Stock Options Outstanding (Detail) (Stock Options Outstanding [Member], USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 27, 2013
Stock Options Outstanding [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of Shares, Vested and expected to vest	7,719
Weighted Average Exercise Price, Vested and expected to vest	$6.94
Weighted Average Remaining Contractual Term (Years), Vested and expected to vest	'3 years 3 months 19 days
Aggregate Intrinsic Value, Vested and expected to vest	$9,532
Number of Shares, Exercisable	5,604
Weighted Average Exercise Price, Exercisable	$7.27
Weighted Average Remaining Contractual Term (Years), Exercisable	'2 years 3 months 19 days
Aggregate Intrinsic Value, Exercisable	$5,516

Employee_Benefit_Plans_Additio

Employee Benefit Plans - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		6 Months Ended	9 Months Ended		6 Months Ended	9 Months Ended	6 Months Ended
	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012	Jun. 30, 2013	Sep. 27, 2013	Aug. 14, 2013	Jun. 30, 2013	Sep. 27, 2013	Jun. 30, 2013
					Employee Stock Purchase Plan [Member]	Employee Stock Purchase Plan [Member]	Employee Stock Purchase Plan [Member]	Minimum [Member]	Maximum [Member]	Maximum [Member]
								Employee Stock Purchase Plan [Member]		Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'	'	'	'
Intrinsic value of options exercised	$1,100,000	$100,000	$2,000,000	$600,000	'	'	'	'	'	'
Percentage of fair market value of Common Stock to purchase shares	'	'	'	'	'	85.00%	'	'	'	'
Range of payroll deductions	'	'	'	'	'1% to 10%	'	'	'	'	'
Employee Stock Purchase Plan Payroll Deductions	'	'	'	'	'	'	'	1.00%	'	10.00%
Percentage of shares available to fund for ESPP	'	'	'	'	'	53.00%	'	'	'	'
Refunded percentage of employee contribution	'	'	'	'	'	47.00%	'	'	'	'
Increase in authorized shares for ESPP	'	'	'	'	'	'	1,000,000	'	'	'
Discretionary contributions of plan	'	'	25.00%	'	'	'	'	'	'	'
Percentage of contribution by eligible participants	'	'	4.00%	'	'	'	'	'	'	'
Maximum contribution per participant	'	'	'	'	'	'	'	'	$1,000	'
Defined contribution plan description	'	'	'Harmonic has a retirement/savings plan which qualifies as a thrift plan under Section 401(k) of the Internal Revenue Code. This plan allows participants to contribute up to the applicable Internal Revenue Code limitations under the plan. Harmonic has made discretionary contributions to the plan of 25% of the first 4% contributed by eligible participants, up to a maximum contribution per participant of $1,000 per year. Harmonic’s contributions were suspended from 2009 through 2012, but have been renewed, on the same basis, for 2013.	'	'	'	'	'	'	'

Employee_Benefit_Plans_Summary2

Employee Benefit Plans - Summary of Restricted Stock Units Outstanding (Detail) (Restricted Stock Units Outstanding [Member], USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013
Restricted Stock Units Outstanding [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of Shares Underlying Restricted Stock Units	2,934
Weighted Average Remaining Vesting Period (Years)	'0 years 10 months 29 days
Aggregate Fair Value	$22,824	[1]
[1]	Represents the fair value of the Company’s common stock as of September 27, 2013, times the number of restricted stock units vested and expected to vest as of the same date.

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation	'	'	$11,953	$14,122
Total stock-based compensation in operating expense	3,340	3,838	10,028	11,571
Total stock-based compensation	3,945	4,497	11,866	13,747
Product cost of revenue [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation	605	659	1,838	2,176
Research and development expense [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation	1,076	1,450	3,400	4,755
Selling, general and administrative expense [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation	$2,264	$2,388	$6,628	$6,816

StockBased_Compensation_Valuat

Stock-Based Compensation - Valuation Assumptions for Stock Options (Detail) (Stock Options [Member])	3 Months Ended		9 Months Ended
	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Stock Options [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Expected term (years)	'4 years 8 months 13 days	'4 years 8 months 13 days	'4 years 8 months 13 days	'4 years 8 months 13 days
Volatility	46.00%	54.00%	51.00%	56.00%
Risk-free interest rate	1.50%	0.70%	0.80%	0.90%
Expected dividends	0.00%	0.00%	0.00%	0.00%

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

6 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

Sep. 27, 2013

Sep. 28, 2012

Sep. 27, 2013

Sep. 28, 2012

Sep. 27, 2013

Sep. 28, 2012

Sep. 27, 2013

Sep. 28, 2012

Jun. 30, 2013

Dec. 31, 2012

Jun. 29, 2012

Sep. 27, 2013

Aug. 14, 2013

Sep. 27, 2013

Sep. 28, 2012

Sep. 27, 2013

Sep. 28, 2012

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Employee Stock Purchase Plan [Member]

Employee Stock Purchase Plan [Member]

Employee Stock Purchase Plan [Member]

Employee Stock Purchase Plan [Member]

Employee Stock Purchase Plan [Member]

Restricted Stock Units Outstanding [Member]

Restricted Stock Units Outstanding [Member]

Restricted Stock Units Outstanding [Member]

Restricted Stock Units Outstanding [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected dividend yield

'

'

'

'

0.00%

0.00%

0.00%

0.00%

0.00%

0.00%

0.00%

'

'

'

'

'

'

Weighted-average fair value per share of options granted

$3.02

$1.89

$2.51

$2.66

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of options vested

$800,000

$800,000

$2,800,000

$3,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Total realized tax benefit

'

'

'

80,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance of restricted stocks fair value

'

'

'

'

'

'

'

'

'

'

'

'

'

2,800,000

2,600,000

10,200,000

10,300,000

Discount percentage on purchase of stock

'

'

'

'

'

'

'

'

'

'

'

15.00%

'

'

'

'

'

Value of stock purchase rights percentage of call option

'

'

'

'

'

'

'

'

'

'

'

85.00%

'

'

'

'

'

Value of stock purchase rights percentage of put option

'

'

'

'

'

'

'

'

'

'

'

15.00%

'

'

'

'

'

Weighted-average fair value per share other than option granted

'

'

'

'

'

'

'

'

$1.23

$1.19

$1.51

'

'

'

'

$5.84

'

Increase in authorized shares for ESPP

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

0

'

0

'

Total unamortized stock-based compensation cost related to unvested stock options and restricted stock units

$20,700,000

'

$20,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Remaining weighted-average amortization period

'

'

'2 years 0 months 0 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_Employ

Stock-Based Compensation - Employee Stock Purchase Plan (Detail) (Employee Stock Purchase Plan [Member])	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 29, 2012
Employee Stock Purchase Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Expected term (years)	'0 years 5 months 28 days	'0 years 6 months 1 day	'0 years 6 months 1 day
Volatility	30.00%	46.00%	53.00%
Risk-free interest rate	0.20%	0.20%	0.20%
Expected dividends	0.00%	0.00%	0.00%

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 27, 2013	Sep. 27, 2013	Sep. 28, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]	'	'	'	'
Unrecognized Tax Benefits that Would Impact the Provision for Income Taxes	$22.30	$22.30	'	$59.20
Federal statutory income tax rate	'	35.00%	35.00%	'
Net decrease in interest and penalties related to uncertain tax positions due to expiration of statute of limitations US and Foreign	'	5.8	'	'
Interest and possible penalties related to uncertain tax positions	1.4	1.4	'	'
Tax Adjustments, Settlements, and Unusual Provisions	$38.40	'	'	'

Income_Loss_Per_Share_Numerato

Income (Loss) Per Share - Numerators and Denominators of Basic and Diluted Net Income (Loss) Per Share Computations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Numerator:	'	'	'	'
Income (Loss) from continuing operations	$36,675	($4,469)	$23,768	($17,079)
Income (loss) from discontinued operations	91	-3,761	15,619	1,338
Net income (loss)	$36,766	($8,230)	$39,387	($15,741)
Denominator:	'	'	'	'
Weighted average number of common shares outstanding Basic	101,144	116,517	108,695	116,946
Effect of dilutive securities from stock options, restricted stock units and ESPP	1,579	0	1,184	0
Weighted average number of common shares outstanding Diluted	102,723	116,517	109,879	116,946
Basic net income (loss) per share from:	'	'	'	'
Continuing operations (usd per share)	$0.36	($0.04)	$0.22	($0.15)
Discontinued operations (usd per share)	$0	($0.03)	$0.14	$0.01
Net income (loss) (usd per share)	$0.36	($0.07)	$0.36	($0.13)
Diluted net income (loss) per share from:	'	'	'	'
Continuing operations (usd per share)	$0.36	($0.04)	$0.22	($0.15)
Discontinued operations (usd per share)	$0	($0.03)	$0.14	$0.01
Net Income (loss) (usd per share)	$0.36	($0.07)	$0.36	($0.13)

Income_Loss_Per_Share_Antidilu

Income (Loss) Per Share - Anti-dilutive Securities (Detail)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Earnings Per Share [Abstract]	'	'	'	'
Potentially dilutive equity awards outstanding	6,144	13,608	10,447	13,382

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	Sep. 27, 2013	Sep. 28, 2012	Oct. 31, 2011
		Patents	Patents
Contingencies And Commitments [Line Items]	'	'	'
Future sublease income from Aurora	$500,000	'	'
Non-cancelable purchase commitments	20,800,000	'	'
Maximum amount of potential future payments under the company's financial guarantees	200,000	'	'
Infringements of number of patents held	'	1	2
Israel [Member]	'	'	'
Contingencies And Commitments [Line Items]	'	'	'
Guarantees which major related to rent	500,000	'	'
Indemnification [Member]	'	'	'
Contingencies And Commitments [Line Items]	'	'	'
Accrual for indemnification provisions	$0	'	'

Commitments_and_Contingencies_2

Commitments and Contingencies - Future Minimum Lease Payments Under Non-cancelable Operating Leases (Detail) (USD $)	Sep. 27, 2013
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
2013 (remaining three months)	$2,645
2014	9,600
2015	9,047
2016	7,811
2017	7,659
Thereafter	21,157
Total	$57,919

Commitments_and_Contingencies_3

Commitments and Contingencies - Summary of Warranty Accrual Included in Accrued Liabilities (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Commitments and Contingencies Disclosure [Abstract]	'	'	'	'
Balance at beginning of period	$3,228	$4,725	$4,292	$5,558
Transfer to Aurora as part of the sale of discontinued operations	0	0	-939	0
Accrual for current period warranties	1,991	1,314	5,333	4,407
Warranty costs incurred	-1,705	-1,677	-5,172	-5,603
Balance at end of period	$3,514	$4,362	$3,514	$4,362

Stockholders_Equity_Components

Stockholders' Equity - Components of Accumulated Other Comprehensive Loss (Detail) (USD $)	Sep. 27, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Equity [Abstract]	'	'
Foreign currency translation adjustments	($510)	($502)
Unrealized gain on investments	43	37
Accumulated Other Comprehensive Loss	($467)	($465)

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	0 Months Ended		1 Months Ended	3 Months Ended	9 Months Ended	18 Months Ended	1 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 27, 2013	Jul. 16, 2013	Jan. 28, 2013	Sep. 27, 2013	Sep. 27, 2013	Sep. 27, 2013	24-May-13	Feb. 19, 2013	Jan. 28, 2013
							Dutch auction [Member]	Common Stock [Member]	Common Stock [Member]
Stock Repurchase Program [Line Items]	'	'	'	'	'	'	'	'	'
Authorized stock repurchase value	'	$220	$25	'	'	'	'	'	'
Increase in stock repurchase program	'	85	'	'	'	'	'	35	75
Common stock repurchased and retired, shares	'	'	'	1.1	4.5	'	'	'	'
Common stock repurchased and retired, aggregate value	'	'	'	7.7	27.6	125.2	'	'	'
Tender offer to repurchased and retired of common stock, shares	'	'	'	'	'	'	12	'	'
Sale of common stock price per share	'	'	'	'	'	'	$6.25	'	'
Tender offer to repurchase of common stock, cost	'	'	'	'	'	'	76	'	'
Fees and expenses on repurchase of common stock	'	'	'	'	'	'	1	'	'
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$94.80	'	'	'	'	'	'	'	'