Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities:
Net income	$ 103,637	$ 53,548	$ 22,644
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	18,931	17,371	17,140
Amortization	2,054	2,669	3,092
Stock-based compensation	11,111	10,482	10,599
Asset impairments and write-offs of intangible assets	1,434	0	0
Other	3	318	(1,999)
Income taxes payable (receivable), net	6,908	(7,926)	3,313
Deferred income taxes	(5,175)	4,814	(869)
(Increase) decrease in:
Receivables	(5,389)	(29,347)	(8,678)
Inventories	(42,337)	(31,398)	(1,160)
Other assets	(11,072)	2,178	(1,120)
Increase (decrease) in:
Accounts payable	1,324	11,812	4,916
Accrued payroll liabilities	15,832	13,183	(1,053)
Accrued warranty reserves	3,077	1,235	1,015
Deferred revenue	(8,544)	18,446	20,036
Accrued restructuring, reorganization, relocation and severance	(2,860)	4,585	(205)
Other liabilities	13,784	3,028	380
Net cash provided by operating activities	102,718	74,998	68,051
Cash flows from investing activities:
Increase in restricted cash	(5,059)	(13,539)	(5,810)
Acquisition of property, plant and equipment	(13,775)	(8,886)	(13,430)
Payments for acquisition activities	(14,050)	0	0
Purchase of investments in marketable securities	(146,571)	(179,698)	(190,654)
Redemption of investments in marketable securities	159,520	261,190	61,107
Proceeds from the sale of auction rate securities	0	98,925	11,200
Other	(992)	(536)	(4,540)
Net cash (used in) provided by investing activities	(20,927)	157,456	(142,127)
Cash flows from financing activities:
Redemption of 2.875% convertible note	0	(10,893)	(13,077)
Withholding taxes paid on issuance of vested restricted stock units	(3,789)	(2,076)	(1,856)
Repayments on line of credit	0	(59,600)	(11,200)
Proceeds from lines of credit	0	0	70,800
Proceeds from exercise of stock options and employee stock purchases	24,382	7,983	6,871
Excess tax benefit for share based payment arrangements	1,425	0	0
Repurchases of common stock	(50,000)	(4,862)	0
Other financing activities	(1,367)	0	0
Net cash (used in) provided by financing activities	(29,349)	(69,448)	51,538
Effect of exchange rate changes	(9,698)	(9,588)	216
Increase (decrease) in cash and cash equivalents	42,744	153,418	(22,322)
Cash and cash equivalents:
Beginning of period	277,617	124,199	146,521
End of period	320,361	277,617	124,199
Supplemental Cash Flow Information:
Cash paid (received) for income taxes, net	9,391	(983)	2,391
Cash paid for interest	3,539	3,833	4,581
Increase (decrease) in fixed assets related to transfers with inventories	9,034	8,697	(8,297)
Increase in goodwill from acquisition-related liabilities	$ 3,456	$ 0	$ 0