Consolidated Statements Of Income (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Consolidated Statements Of Income
Revenues	$ 104,027	$ 90,996	$ 204,751	$ 176,307
Cost of revenues	54,565	47,441	107,198	91,063
Gross profit	49,462	43,555	97,553	85,244
Operating expenses:
Research and development	14,251	12,465	27,702	22,188
Selling, general and administrative	19,763	20,446	42,745	40,418
Total operating expenses	34,014	32,911	70,447	62,606
Operating income	15,448	10,644	27,106	22,638
Interest income	289	222	713	428
Other expense, net	(8)	(129)	(132)	(95)
Income before income taxes	15,729	10,737	27,687	22,971
Provision for income taxes	4,595	3,139	8,546	6,707
Net income	$ 11,134	$ 7,598	$ 19,141	$ 16,264
Earnings per common share - basic	$ 0.35	$ 0.24	$ 0.60	$ 0.52
Weighted average shares outstanding - basic	31,665	31,509	31,674	31,527
Earnings per common share - diluted	$ 0.34	$ 0.24	$ 0.59	$ 0.51
Weighted average shares outstanding - diluted	32,328	31,938	32,325	31,985