Restructuring and Related Charges - Activities in Restructuring Accrual (Detail) (USD $)	3 Months Ended	12 Months Ended
Apr. 03, 2015	Mar. 28, 2014	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Product cost of revenue	$ 0	$ 79,000
Restructuring and related charges	44,000us-gaap_RestructuringCharges	149,000us-gaap_RestructuringCharges
Restructuring and Related Cost, Incurred Cost	44,000	228,000
Harmonic Two Thousand And Fifteen Restructuring [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	322,000
Restructuring charges	56,000		2,200,000
Adjustments to restructuring provisions	(12,000)
Cash payments	(321,000)
Non-cash write-offs	2,000
Ending Balance	47,000		322,000
Harmonic Two Thousand And Fifteen Restructuring [Member] \| Employee Severance And Benefit Arrangements [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	44,000
Restructuring Reserve [Roll Forward]
Beginning Balance	305,000
Restructuring charges	56,000		600,000
Adjustments to restructuring provisions	(5,000)
Cash payments	(312,000)
Non-cash write-offs	0
Ending Balance	44,000		305,000
Harmonic Two Thousand And Fifteen Restructuring [Member] \| Other Restructuring [Member]
Restructuring Reserve [Roll Forward]
Beginning Balance	17,000
Restructuring charges	0		100,000
Adjustments to restructuring provisions	(7,000)
Cash payments	(9,000)
Non-cash write-offs	2,000
Ending Balance	$ 3,000		$ 17,000

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes, but is not limited to, one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and termination benefits associated with an ongoing benefit arrangement. Excludes expenses associated with special or contractual termination benefits, a discontinued operation or an asset retirement obligation.

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-Name Accounting Standards Codification

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-Name Staff Accounting Bulletin (SAB)

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Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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- Definition

Nonrecurring impairment charges related to the write-off of production-related equipment and inventory. This tag is used when an Entity charges this cost to cost of goods sold.

+ References

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-Publisher FASB

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- Definition

Discloses the amount charged against the accrued restructuring reserves, or earnings if not previously accrued, during the period for the specified type of restructuring cost.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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Amount of any reversal and other adjustment made during the period to the amount of a previously accrued liability for a specified type of restructuring cost, excluding adjustments for costs incurred during the period, costs settled during the period, and foreign currency translation adjustments.

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- Definition

Amount of consideration other than cash used to fully or partially settle an accrued restructuring cost.

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