Segments Summary of revenue by product line (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue from External Customer [Line Items]
Product	$ 62,393	$ 65,028	$ 50,322
Service	40,105	35,929	29,181
Total revenue	102,498	100,957	79,503
Devices
Revenue from External Customer [Line Items]
Product	46,636	47,725	37,088
Software
Revenue from External Customer [Line Items]
Product	15,757	17,303	13,234
Maintenance and support
Revenue from External Customer [Line Items]
Service	31,559	26,237	21,439
Professional services and training
Revenue from External Customer [Line Items]
Service	$ 8,546	$ 9,692	$ 7,742