Short-Term Investments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities in material unrealized loss position	$ 0

Available For Sale Securities In A Material Unrealized Loss Position

No definition available.

Name:	hlit_AvailableForSaleSecuritiesInMaterialUnrealizedLossPosition
Namespace Prefix:	hlit_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant