Stock-Based Compensation (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Summary of stock-based compensation expense
Share-based compensation expense	$ 762	$ 607	$ 2,101	$ 2,957
Remaining unamortized expense of stock-based compensation	2,242		2,242
Product research and development [Member]
Summary of stock-based compensation expense
Share-based compensation expense	187	73	69	260
Sales and marketing [Member]
Summary of stock-based compensation expense
Share-based compensation expense	749	250	364	1,200
General and administrative [Member]
Summary of stock-based compensation expense
Share-based compensation expense	$ 1,165	$ 284	$ 329	$ 1,497