Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenue	$ 111,784	$ 106,394
Costs and expenses
Cost of revenue	49,601	47,448
Selling, general and administrative	22,498	18,003
Research and development	9,314	9,718
Total costs and expenses	81,413	75,169
Operating income	30,371	31,225
Equity in net loss of affiliate	(2,387)	(2,356)
Income before interest and income tax expense	27,984	28,869
Interest income	22	20
Interest expense	165	129
Income before income tax expense	27,841	28,760
Income tax expense	11,551	10,953
Net income	$ 16,290	$ 17,807
Income per weighted-average common share
Basic	$ 0.61	$ 0.65
Diluted	$ 0.60	$ 0.64
Weighted-average common shares used in calculations
Basic	26,686	27,246
Potentially dilutive securities	594	496
Diluted	27,280	27,742
Dividends declared per common share outstanding	$ 0.10	$ 0.10