Statement of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Operations [Abstract]
Revenues	$ 218,486	$ 187,196	$ 195,305
Cost of Revenue	102,811	86,843	91,405
Gross Profit	115,675	100,353	103,900
Research and Development Expense	39,331	36,298	33,387
Selling, General and Administrative Expense	40,225	40,826	38,173
Amortization of Intangible Assets	1,853	1,757	1,715
Operating Expenses	81,409	78,881	73,275
Operating Income (Loss)	34,266	21,472	30,625
Interest Income (Expense), Net	(4,377)	(1,925)	167
Other Nonoperating Income (Expense)	(482)	847	(255)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	29,407	20,394	30,537
Income Tax Expense (Benefit)	(14,458)	(4,832)	3,522
Net Income (Loss) Attributable to Parent	$ 43,865	$ 25,226	$ 27,015
Earnings Per Share, Basic	$ 1.36	$ 0.79	$ 0.86
Earnings Per Share, Diluted	$ 1.34	$ 0.78	$ 0.86
Weighted Average Number of Shares Outstanding, Basic	32,226	31,744	31,286
Weighted Average Number of Shares Outstanding, Diluted	32,853	32,256	31,492