Income Taxes - Significant Components of Net Deferred Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Components Of Deferred Tax Assets And Liabilities [Abstract]
Allowance for doubtful accounts	$ 20	$ 115
Inventory reserves	1,340	1,697
Accrued liabilities	76	316
Warrant interest expense	277	277
Stock compensation expense	2,850	2,503
State net operating loss-net of tax	3,500	1,524
Net operating loss carryforward	16,206	4,537
Unrealized loss on securities held for sale	240
Tax credits	514	297
Valuation allowance	(9,547)
Total deferred tax assets	15,476	11,266
Deferred tax liability:
Depreciation	(15,620)	(16,685)
Unrealized gain on securities held for sale		(340)
Prepaid expenses	(123)	(140)
Net deferred tax liability	$ (267)	$ (5,899)