Preparation of Interim Financial Statements - Additional Information (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Wireless revenue, net	$ 33,518,000	$ 37,771,000	$ 67,869,000	$ 76,550,000
Software revenue, net	15,576,000	14,497,000	31,344,000	28,848,000
Cost of revenue	7,180,000	6,961,000	13,985,000	13,628,000
Service, rental and maintenance	11,420,000	12,018,000	23,212,000	24,209,000
Selling and marketing	7,780,000	6,538,000	15,026,000	12,932,000
General and administrative	10,990,000	11,022,000	23,125,000	23,353,000
Total operating expenses	41,726,000	40,363,000	83,753,000	81,753,000
Operating income	7,368,000	11,905,000	15,460,000	23,645,000
Scenario, Previously Reported [Member]
Wireless revenue, net		36,370,000
Restatement Adjustment [Member]
Wireless revenue, net		1,401,000
Cost of revenue		1,476,000
Service, rental and maintenance		(804,000)
Selling and marketing		191,000
General and administrative		(863,000)
Total operating expenses		0
Operating income		$ 0