Stock Plans (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Stock-based compensation expense
Total stock-based compensation expense	$ 1,762	$ 578	$ 3,596	$ 1,154
Cost of revenues [Member]
Stock-based compensation expense
Total stock-based compensation expense	143	29	302	73
Research and development [Member]
Stock-based compensation expense
Total stock-based compensation expense	372	35	759	83
Sales and marketing [Member]
Stock-based compensation expense
Total stock-based compensation expense	665	102	1,365	245
General and administrative [Member]
Stock-based compensation expense
Total stock-based compensation expense	$ 582	$ 412	$ 1,170	$ 753