Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Total revenues	$ 39,133	$ 35,204	$ 89,454	$ 96,905
Costs and expenses
Cost of sales (excludes amortization of intangible assets of $1,590, $1,590, $3,180 and $3,161, respectively)	17,318	15,493	36,567	36,605
Research and development	9,656	9,105	22,363	17,156
Sales and marketing	12,206	11,923	24,523	23,711
General and administrative	6,682	6,290	13,971	16,150
Amortization of intangible assets from acquired businesses and technology	2,290	2,218	4,509	4,419
Total costs and expenses	48,152	45,029	101,933	98,041
Operating loss	(9,019)	(9,825)	(12,479)	(1,136)
Interest expense, net	(2,924)	(3,061)	(5,613)	(5,956)
Loss before taxes	(11,943)	(12,886)	(18,092)	(7,092)
Benefit for income taxes	(4,103)	(3,955)	(6,806)	(2,152)
Net loss	$ (7,840)	$ (8,931)	$ (11,286)	$ (4,940)
Basic and diluted loss per share (in dollars per share)	$ (0.24)	$ (0.26)	$ (0.35)	$ (0.14)
Shares used in basic and diluted per share (weighted-average common shares outstanding)	32,541	34,597	32,632	34,611