Preparation of Interim Financial Statements - Additional Information (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Wireless revenue, net	$ 32,855,000	$ 37,067,000	$ 100,724,000	$ 113,617,000
Software revenue, net	16,936,000	12,602,000	48,280,000	41,450,000
Cost of revenue	8,000,000	6,787,000	21,985,000	20,415,000
Service, rental and maintenance	10,988,000	11,820,000	34,200,000	36,029,000
Selling and marketing	7,072,000	6,388,000	22,098,000	19,320,000
General and administrative	10,866,000	11,282,000	33,991,000	34,635,000
Total operating expenses	41,718,000	40,135,000	125,471,000	121,888,000
Operating income	8,073,000	9,534,000	23,533,000	33,179,000
Scenario, Previously Reported [Member]
Wireless revenue, net		35,540,000
Restatement Adjustment [Member]
Wireless revenue, net		1,530,000
Cost of revenue		1,430,000
Service, rental and maintenance		(730,000)
Selling and marketing		150,000
General and administrative		(850,000)
Total operating expenses		0
Operating income		$ 0