Consolidated Statements of Operations (USD $)
In Thousands, except Per Share data, unless otherwise specified
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Revenue $ 238,091 $ 213,813 $ 196,519
Cost of revenue 110,190 100,665 94,925
Gross profit 127,901 113,148 101,594
Operating expenses:      
Research and development 49,733 48,796 44,518
Selling, general and administrative 54,624 50,018 40,280
Litigation expense (benefit), net (371) (2,945) 3,379
Total operating expenses 103,986 95,869 88,177
Income from operations 23,915 17,279 13,417
Interest and other income, net 92 611 309
Income before income taxes 24,007 17,890 13,726
Income tax provision 1,109 2,134 425
Net income $ 22,898 $ 15,756 $ 13,301
Basic net income per share (in Dollars per share) $ 0.61 $ 0.45 $ 0.39
Diluted net income per share (in Dollars per share) $ 0.59 $ 0.43 $ 0.38
Weighted average common shares outstanding:      
Basic (in Shares) 37,387 34,871 34,050
Diluted (in Shares) 38,620 36,247 35,160