CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Wireless	$ 109,590	$ 119,014	$ 132,402
Software	69,971	70,614	67,871
Total revenue	179,561	189,628	200,273
Operating expenses:
Cost of revenue	30,649	33,851	32,556
Research and development	13,467	10,280	9,501
Service, rental and maintenance	32,734	34,121	35,984
Selling and marketing	24,768	27,446	30,013
General and administrative	41,381	42,159	45,896
Severance	1,446	2,701	1,495
Depreciation, amortization and accretion	12,963	13,970	16,677
Total operating expenses	157,408	164,528	172,122
Operating income	22,153	25,100	28,151
Interest income (expense)	275	16	(456)
Other income (expense)	543	1,182	(368)
Income before income tax expense	22,971	26,298	27,327
Income tax benefit (expense)	(8,992)	53,948	(6,582)
Net income	$ 13,979	$ 80,246	$ 20,745
Basic and diluted net income per common share (usd per share)	$ 0.68	$ 3.74	$ 0.96
Basic and diluted weighted average common shares outstanding (shares)	20,586,066	21,471,041	21,644,163
Cash dividends declared per common share (usd per share)	$ 0.750	$ 0.625	$ 0.500