Operations And Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
	Jan. 21, 2011 item	Dec. 31, 2012 segment	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Line Items]
Fair value of short-term investments in debt securities		$ 173,166,000	$ 223,504,000
German government sovereign debt, in USD		25,000,000
Net of allowances for sales returns		2,100,000	1,600,000
Net of allowances for doubtful accounts		2,800,000	2,600,000
Inventory, net of adjustment for excess and obsolete inventories		3,800,000	4,200,000	3,300,000
Intangible assets estimated economic life		5 years
Goodwill impairment		0	0
Number of operating segments (alloocated to goodwill impairment testing)		1
Cash and cash equivalents		161,996,000	142,608,000	219,447,000	201,465,000
Investment policy for marketable securities		Our investment policy for marketable securities requires that all securities mature in three years or less, with a weighted average maturity of no longer than 18 months with at least 10% maturing in 90 days or less.
Percentage of sales to any individual customer to total revenue		7.00%	4.00%	4.00%
Largest trade account receivable from any individual customer		15,000,000
Licensing and sales arrangement payment term, minimum (in days)		30 days
Concentrated orders		1,000,000
Licensing and sales arrangement payment term, maximum (in days)		120 days
Maximum period of return after delivering of product (in days)		30 days
Warranty on products, minimum (in days)		90 days
Warranty on Products, maximum (in years)		3 years
Deferred revenue - current		90,714,000	80,059,000
Advertising expense		14,400,000	14,700,000	13,200,000
Anti-dilutive securities excluded from the computation of diluted EPS		986,503	477,019	322,896
Stock split conversion ratio	1.5
Date of stock split declared		January 21, 2011
Comprehensive income		94,481,000	91,282,000	94,861,000
Money Market Accounts [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		21,000,000
Percentage of cash and cash equivalents		13.00%
Domestic Financial Institutions [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		26,000,000
Percentage of cash and cash equivalents		16.00%
Non U.S. Financial Institutions [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		136,000,000
Percentage of cash and cash equivalents		84.00%
Foreign Government Bonds [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of short-term investments in debt securities		25,000,000
Percentage of short-term investments		14.00%
U.S. Treasuries And Agencies [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of short-term investments in debt securities		136,000,000
Percentage of short-term investments		79.00%
Municipal Bonds [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of short-term investments in debt securities		1,500,000
Percentage of short-term investments		1.00%
Corporate Bonds [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of short-term investments in debt securities		8,000,000
Percentage of short-term investments		4.00%
Time Deposits [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of short-term investments in debt securities		3,000,000
Percentage of short-term investments		2.00%
Hong Kong Operating Account [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		26,000,000
Percentage of cash and cash equivalents		16.00%
Cash [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		$ 141,000,000
Percentage of cash and cash equivalents		87.00%