Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current
Accrued liabilities	$ 1,786	$ 1,182
Intangible assets	22	0
Other	28
Total assets	1,836	1,182
Long- term
Intangible assets	2,005	2,712
Net operating loss carryforward	7,367	2,457
Non-qualified stock options	1,113	291
Other	1,499	413
Total assets	11,984	5,873
Current
Deferred revenue on maintenance contracts	(1,738)	0
Other	(61)
Total liabilities	(1,799)	0
Long- term
Depreciation and amortization	(27,845)	(25,355)
Goodwill and gain on purchase of a business	(2,635)	(1,738)
Other	0	(67)
Total liabilities	(30,480)	(27,160)
Net current deferred tax assets	37	1,182
Net non-current deferred tax liabilities	$ 18,496	$ 21,287