CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Revenue	$ 37,260	$ 46,642	$ 72,626	$ 78,900
Cost of goods sold	13,378	17,191	25,656	27,571
Gross profit	23,882	29,451	46,970	51,329
Operating costs:
Sales and marketing	10,470	9,856	20,101	19,264
Research and development	5,345	4,796	10,192	9,497
General and administrative	5,492	5,330	10,944	10,405
Amortization of purchased intangible assets	651	472	1,093	951
Total operating costs	21,958	20,454	42,330	40,117
Operating income	1,924	8,997	4,640	11,212
Interest income, net	40	68	82	145
Other income, net	265	300	413	532
Income from continuing operations before income taxes	2,229	9,365	5,135	11,889
Provision for income taxes	379	1,967	873	2,497
Net income from continuing operations	1,850	7,398	4,262	9,392
Income (loss) from discontinued operations	(41)	(236)	333	(319)
Net income	$ 1,809	$ 7,162	$ 4,595	$ 9,073
Basic income (loss) per share
Continuing	$ 0.05	$ 0.19	$ 0.11	$ 0.25
Discontinued	$ 0.00	$ (0.01)	$ 0.01	$ (0.01)
Total	$ 0.05	$ 0.18	$ 0.12	$ 0.24
Diluted income (loss) per share
Continuing	$ 0.05	$ 0.19	$ 0.11	$ 0.24
Discontinued	$ 0.00	$ (0.01)	$ 0.01	$ (0.01)
Total	$ 0.05	$ 0.18	$ 0.12	$ 0.23
Weighted average common shares outstanding:
Basic	38,908	38,065	38,798	37,928
Diluted	39,226	38,742	39,145	38,597