Income Taxes (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Allowance for doubtful accounts	$ 115	$ 156
Inventory reserves	1,697	400
Accrued liabilities	316	260
Warrant interest expense	277	283
Charitable contributions		10
Stock compensation expense	2,503	2,083
Net operating loss carryforward	4,537
State net operating loss-net of tax	1,524	984
Tax credits	297	206
Total deferred tax assets	11,266	4,382
Deferred tax liability:
Depreciation	(16,685)	(16,310)
Unrealized gain on securities held for sale	(340)
Prepaid expenses	(140)	(115)
Net deferred tax liability	$ (5,899)	$ (12,043)