Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 28,938	$ 26,827
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	14,262	13,687
Provision for doubtful accounts	(143)	509
Provision for warranty and returns	291	0
Stock compensation	4,361	2,998
Loss (gain) on disposal of property and equipment	41	(57)
Bond premium amortization	1,660	801
Cash provided (used) by changes in operating assets and liabilities
Accounts receivable	(9,790)	1,575
Inventories	2,974	1,143
Prepaid expenses and other assets	792	(2,406)
Accounts payable	(943)	(272)
Accrued liabilities	682	(1,698)
Deferred revenue	0	(254)
Prepaid and deferred income taxes	(2,194)	(6,802)
Net cash provided by operating activities	40,931	36,051
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(13,208)	(13,761)
Proceeds from sale of asset	10	0
Intangible assets acquired	(951)	0
Proceeds from insurance	0	2,781
Purchases of investment securities	(78,534)	(66,330)
Proceeds from sale of investment securities	60,452	26,935
Net cash used by investing activities	(32,231)	(50,375)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	13,214	7,021
Proceeds from employee stock purchase plan	2,220	909
Tax benefits from exercise of stock options	4,002	3,682
Payments for Repurchase of Common Stock	0	(9,992)
Net cash provided by financing activities	19,436
Effect of exchange rate changes on cash	(202)	793
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	27,934	(11,911)
CASH AND CASH EQUIVALENTS, beginning of period	99,590	78,850
CASH AND CASH EQUIVALENTS, end of period	127,524	66,939
NON-CASH INVESTING ACTIVITIES
Accrued liabilities for property and equipment	$ 288	$ 557