Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current
Accrued liabilities	$ 1,913	$ 1,786
Intangible assets	121	22
Other	23	28
Total assets	2,057	1,836
Long- term
Intangible assets	2,219	2,005
Net operating loss carryforward	10,604	7,367
Non-qualified stock options	1,268	1,113
Other	1,170	1,499
Total assets	15,261	11,984
Current
Deferred revenue on maintenance contracts	(1,327)	(1,738)
Other	(4)	(61)
Total liabilities	(1,331)	(1,799)
Long- term
Depreciation and amortization	(30,082)	(27,845)
Goodwill and gain on purchase of a business	(3,157)	(2,319)
Other	0	0
Total liabilities	(33,239)	(30,164)
Net current deferred tax assets	726	37
Net non-current deferred tax liabilities	$ 17,978	$ 18,180