Credit Facilities - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012
Debt Instrument [Line Items]
Maximum borrowing capacity under bank line of credit facility	$ 10,000,000
Bank line of credit facility, maturity date	Aug. 23, 2013
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 financial covenant terms	4.11 to 1
Interest rate	3.25%
Annualized rate of LIBOR	0.21%
Credit facility collateral	Borrowings are not collateralized
Covenants under the line of credit facility	At December 31, 2012, Harmonic was in compliance with the covenants under the line of credit facility.
Minimum [Member]
Debt Instrument [Line Items]
Percentage added to LIBOR to facilitate line of credit	1.75%
Maximum [Member]
Debt Instrument [Line Items]
Percentage added to LIBOR to facilitate line of credit	1.96%