Stock-Based Compensation (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary of stock-based compensation expense
Total stock based compensation expense	$ 1,729	$ 2,656	$ 3,499
Remaining unamortized expense of stock-based compensation	880
Product Research and Development [Member]
Summary of stock-based compensation expense
Total stock based compensation expense	510	267	315
Sales and Marketing [Member]
Summary of stock-based compensation expense
Total stock based compensation expense	353	909	1,407
General and Administrative [Member]
Summary of stock-based compensation expense
Total stock based compensation expense	$ 866	$ 1,480	$ 1,777