Defined Contribution Plan Employer Discretionary Maximum Contribution Amount Per Participant

No definition available.

Name:	hlit_DefinedContributionPlanEmployerDiscretionaryMaximumContributionAmountPerParticipant
Namespace Prefix:	hlit_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Employee Stock Purchase Plan Payroll Deductions

+ References

No definition available.

+ Details

Name:	hlit_EmployeeStockPurchasePlanPayrollDeductions
Namespace Prefix:	hlit_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Refunded Percentage Of Employee Contribution

+ References

No definition available.

+ Details

Name:	hlit_RefundedPercentageOfEmployeeContribution
Namespace Prefix:	hlit_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Plan assets of a defined benefit plan, as a percentage of projected benefit obligation.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedBenefitPlanFundedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the terms and benefits provided by the employer's defined contribution plans. A defined contribution plan provides benefits in return for services rendered, provides an individual account for each participant, and has terms that specify how contributions to the individual's account are to be determined rather than the amount of benefits the individual is to receive. Under a defined contribution pension plan, the benefits a participant will receive depend solely on the amount contributed to the participant's account, the returns earned on investments of those contributions, and forfeitures of other participants' benefits that may be allocated to such participant's account. A description of the plan(s) including employee groups covered, the basis for determining contributions, and the nature and effects of significant matters affecting comparability of information for all periods presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Defined Contribution Postretirement Plan

-URI http://asc.fasb.org/extlink&oid=6510416

+ Details

Name:	us-gaap_DescriptionOfDefinedContributionPensionAndOtherPostretirementPlans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Purchase price of common stock expressed as a percentage of its fair value.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Employee Benefit Plans - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended				0 Months Ended		3 Months Ended	9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013	Sep. 26, 2014	Sep. 27, 2013	Sep. 26, 2014 Employee Stock Purchase Plan [Member]	Sep. 27, 2013 Employee Stock Purchase Plan [Member]	Jul. 29, 2014 Employee Stock Purchase Plan [Member]	Aug. 14, 2013 Employee Stock Purchase Plan [Member]	Sep. 26, 2014 Employee Stock Purchase Plan [Member]	Sep. 26, 2014 Minimum [Member] Employee Stock Purchase Plan [Member]	Sep. 26, 2014 Maximum [Member] Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$ 300,000	$ 1,100,000	$ 700,000	$ 2,000,000
Percentage of fair market value of Common Stock to purchase shares					85.00%				85.00%
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			350,000				1,000,000	1,000,000
Discretionary contributions of plan			25.00%
Percent of employees' gross pay eligible for matching			4.00%
Maximum contribution amount per participant			1,000
Contributions in period			$ 354,000	$ 387,000
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.