Consolidated Statements Of Cash Flows (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Operating activities
Net income	$ 19,141	$ 16,264
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	13,572	13,499
Deferred income taxes	1,351	(457)
Stock-based compensation expense	4,130	4,308
Gain on remeasurement of contingent consideration	(921)
Other	1,561	1,047
Changes in operating assets and liabilities:
Accounts receivable	412	(1,931)
Inventories	(5,149)	(3,212)
Other assets	(412)	(5,089)
Accounts payable	311	2,024
Accrued expenses, income taxes and other liabilities	(3,131)	5,766
Net cash provided by operating activities	30,865	32,219
Investing activities
Capital expenditures	(9,115)	(6,455)
Purchases of marketable securities	(62,176)	(51,159)
Proceeds from sales or maturities of marketable securities	53,371	20,042
Acquisition of cost-basis investment	(6,746)
Other	49	4
Net cash used for investing activities	(24,617)	(37,568)
Financing activities
Purchases of treasury stock	(824)	(704)
Proceeds from exercise of stock options	762	137
Credit line borrowings		1,724
Credit line repayments		(2,207)
Other	(22)	(31)
Net cash used for financing activities	(84)	(1,081)
Effects of exchange rate changes on cash and cash equivalents	(633)	234
Net increase (decrease) in cash and cash equivalents	5,531	(6,196)
Cash and cash equivalents, beginning of period	68,648	64,738
Cash and cash equivalents, end of period	$ 74,179	$ 58,542