Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Inventories [Abstract]
Reserves for obsolete inventory	$ 5,500,000	$ 7,100,000
Raw materials	32,332,000	24,668,000
Finished goods	103,542,000	87,443,000
Inventories	135,874,000	112,111,000
Revenue recognition [Abstract]
Accrued reserve for product returns	6,200,000	5,200,000
Sales returns	56,100,000	56,500,000	55,400,000
Fair value of financial instruments [Abstract]
Long-term debt, fair value	199,500,000	145,000,000
Advertising expense [Abstract]
Advertising expense incurred	5,100,000	2,300,000	2,100,000
Selling expenses [Abstract]
Number of levels of executive distributors	6
Research and development [Abstract]
Research and development expense	14,900,000	13,600,000	12,400,000
Deferred tax assets and liabilities [Abstract]
Net deferred tax assets	35,635,000	51,449,000
Reconciliation of Unrecognized Tax Benefits [Abstract]
Gross Balance, Beginning	7,387,000	14,821,000	28,275,000
Increases related to prior year tax positions	0	(7,138,000)	(1,206,000)
Increases related to current year tax positions	2,430,000	1,415,000	2,236,000
Settlements	0	(499,000)	0
Decreases due to lapse of statutes of limitations	(854,000)	(1,255,000)	(15,395,000)
Currency adjustments	82,000	43,000	911,000
Gross Balance, Ending	9,045,000	7,387,000	14,821,000
Unrecognized tax benefits that would impact effective tax rate	3,800,000	3,100,000
Estimate of change in gross unrecognized tax benefits, net of foreign adjustments, minimum	2,000,000
Estimate of change in gross unrecognized tax benefits, net of foreign currency adjustments, maximum	4,000,000
Interest and penalties expenses/(benefits)	300,000	800,000	(1,700,000)
Accrued interest and penalties related to uncertain tax positions	$ 1,100,000	$ 800,000	$ 1,600,000
Leasehold Improvements [Member]
Property and equipment [Abstract]
Estimated useful life description	Shorter of estimated useful life or lease term