Unaudited Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]
Revenue	$ 105,318	$ 93,586	$ 207,893	$ 171,829
Cost of revenue	63,008	55,992	121,903	101,605
Gross margin	42,310	37,594	85,990	70,224
Expenses:
Selling, general and administrative	20,854	21,081	42,426	39,098
Depreciation and amortization	2,501	2,003	4,785	3,193
Research and development	1,280	979	2,306	1,854
Total expenses	24,635	24,063	49,517	44,145
Income from operations	17,675	13,531	36,473	26,079
Other income (expense):
Interest expense	(381)	(531)	(836)	(965)
Other income (expense), net	(272)	170	(218)	58
Total other income (expense)	(653)	(361)	(1,054)	(907)
Income before income taxes	17,022	13,170	35,419	25,172
Income tax expense	(5,981)	(4,730)	(12,361)	(8,967)
Net income	$ 11,041	$ 8,440	$ 23,058	$ 16,205
Earnings per common share:
Basic earnings per common share	$ 0.20	$ 0.17	$ 0.42	$ 0.33
Diluted earnings per common share	$ 0.20	$ 0.16	$ 0.42	$ 0.31
Weighted average common shares:
Weighted average common shares used in computing basic earnings per common share	54,645	51,086	54,299	49,841
Weighted average common shares used in computing diluted earnings per common share	55,533	53,713	55,473	52,445