Segments Summary of the operating segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Segments	Sep. 30, 2011
Segment Reporting Information [Line Items]
Number of reportable segments			2
Total revenue	$ 25,968	$ 20,401	$ 73,965	$ 57,797
Gross profit	16,988	12,250	46,693	35,260
Research and development	3,043	2,379	8,248	6,970
Sales and marketing	8,532	7,542	24,064	20,717
General and administrative	3,745	3,197	10,449	8,278
Income (loss) from operations	1,668	(868)	3,932	(705)
Interest income	60	5	86	13
Interest expense and other finance charges	0	(112)	(74)	(234)
Other income (expense), net	50	132	(1,442)	(1,085)
Income (loss) before income taxes	1,778	(843)	2,502	(2,011)
Products
Segment Reporting Information [Line Items]
Total revenue	16,851	13,087	47,643	36,648
Product	16,851	13,087	47,643	36,648
Gross profit	11,614	8,797	31,505	24,680
Services
Segment Reporting Information [Line Items]
Total revenue	9,117	7,314	26,322	21,149
Service	9,117	7,314	26,322	21,149
Gross profit	$ 5,374	$ 3,453	$ 15,188	$ 10,580