Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Total revenues	$ 182,615	$ 175,410	$ 155,741
Costs and expenses
Cost of sales (excludes amortization of intangible assets of $6,283, $6,079, and $5,753, respectively)	74,180	66,976	61,285
Research and development	37,913	34,186	27,716
Sales and marketing	41,533	33,829	30,319
General and administrative	25,811	25,581	19,800
Amortization of intangible assets from acquired businesses and technology	8,828	8,171	6,935
Impairment loss	3,558	0	0
Facility restructuring charges	0	1,825	0
Total costs and expenses	191,823	170,568	146,055
Operating (loss) income	(9,208)	4,842	9,686
Interest expense, net	(1,775)	(1,408)	(2,075)
(Loss) income before (benefit) provision for income taxes	(10,983)	3,434	7,611
(Benefit) provision for income taxes	(3,909)	(3,956)	2,618
Net (loss) income	$ (7,074)	$ 7,390	$ 4,993
Basic (loss) earnings per share	$ (0.21)	$ 0.22	$ 0.15
Diluted (loss) earnings per share	$ (0.21)	$ 0.21	$ 0.15
Shares used in basic per share calculations	34,451	33,836	33,068
Shares used in diluted per share calculations	34,451	34,947	33,702