Consolidated Condensed 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 (loss)	$ 69,869	$ 61,381	$ (4,869)
Adjustments to reconcile net income (loss) to net cash provided by operations:
Intangible asset impairment charge (Note 7)			1,000
Stock-based compensation expense	8,068	3,027	9,223
Depreciation of property, plant and equipment	5,529	4,685	4,701
Amortization of intangible assets	4,227	5,124	4,879
Amortization of discounts or premiums on investments	6,383	3,195	1,512
Change in deferred income taxes	(425)	1,034	1,985
Tax effect of stock option exercises	(4,045)	(1,941)	472
Change in operating assets and liabilities:
Accounts receivable	(2,031)	(14,535)	(287)
Inventories	(5,743)	(6,190)	8,618
Accrued expenses	2,747	10,134	(3,208)
Accrued income taxes	(2,865)	9,567	(6,611)
Deferred revenue and customer deposits	3,316	(4,740)	(4,532)
Return of Japan tax deposit (Note 16)		9,336
Other	1,064	(3,734)	(600)
Net cash provided by operating activities	86,094	76,343	12,283
Cash flows from investing activities:
Purchases of investments	(323,946)	(253,867)	(33,779)
Maturities and sales of investments	241,738	82,918	43,720
Purchases of property, plant, and equipment	(7,820)	(5,852)	(5,466)
Cash paid for business acquisitions, net of cash acquired			(4,941)
Cash received related to discontinued business		315
Net cash used in investing activities	(90,028)	(176,486)	(466)
Cash flows from financing activities:
Issuance of common stock under stock option and stock purchase plans	30,863	28,384	146
Payment of dividends	(15,114)	(10,014)	(11,897)
Repurchase of common stock	(10,000)
Stock option buyback (Note 14)		(83)	(9,075)
Tax effect of stock option exercises	4,045	1,941	(472)
Net cash provided by (used in) financing activities	9,794	20,228	(21,298)
Effect of foreign exchange rate changes on cash	(960)	(6,713)	2,174
Net change in cash and cash equivalents	4,900	(86,628)	(7,307)
Cash and cash equivalents at beginning of year	33,203	119,831	127,138
Cash and cash equivalents at end of year	$ 38,103	$ 33,203	$ 119,831