Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Total revenues	$ 49,341	$ 46,812	$ 138,795	$ 143,717
Costs and expenses
Cost of sales (excludes amortization of intangible assets of $1,590, $1,590, $4,770 and $4,751, respectively)	17,728	16,961	54,295	53,566
Research and development	8,801	8,419	31,164	25,575
Sales and marketing	11,853	12,112	36,376	35,823
General and administrative	6,561	5,889	20,532	22,039
Amortization of intangible assets from acquired businesses and technology	2,273	2,219	6,782	6,638
Total costs and expenses	47,216	45,600	149,149	143,641
Operating income (loss)	2,125	1,212	(10,354)	76
Interest expense, net	(3,006)	(3,090)	(8,619)	(9,046)
Loss before taxes	(881)	(1,878)	(18,973)	(8,970)
Benefit for income taxes	(309)	(1,116)	(7,115)	(3,268)
Net loss	$ (572)	$ (762)	$ (11,858)	$ (5,702)
Basic and diluted loss per share (in dollars per share)	$ (0.02)	$ (0.02)	$ (0.36)	$ (0.17)
Shares used in basic and diluted per share (weighted-average common shares outstanding)	32,673	33,683	32,645	34,313