Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current
Accrued liabilities	$ 3,073	$ 2,714
Intangible assets	0	111
Non-qualified stock options	31	45
Other	44	44
Total assets	3,148	2,914
Long- term
Intangible assets	2,983	1,935
Net operating loss carryforward	4,597	3,797
Valuation Allowance	(1,552)	0	$ 0
Non-qualified stock options	1,354	1,248
Foreign tax credits	1,501	1,078
AMT credits	995	993
Other	32	(16)
Total assets	9,910	9,035
Current
Deferred revenue on maintenance contracts	(8)	(1,121)
Other	(32)	(38)
Total liabilities	(40)	(1,159)
Net current deferred tax assets	3,108	1,755
Long- term
Depreciation and amortization	(24,309)	(26,173)
Goodwill	(4,933)	(3,753)
Deferred revenue on maintenance contracts	0	14
Other	(13)	0
Total liabilities	(29,255)	(29,912)
Net non-current deferred tax liabilities	$ (19,345)	$ (20,877)