Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Net operating loss carry forward	$ 40,639	$ 45,927
Federal and state tax credits	2,168	1,944
Deferred revenue	293	312
Depreciation and amortization	9,785	14,162
Allowance and accrued liabilities	1,162	1,389
Share-based compensation expense	351	445
Capitalized research and development	1,978	3,958
Total deferred tax assets	56,376	68,137
Valuation allowance	(48,258)	(60,019)
Net deferred tax assets	8,118	8,118
Deferred tax liabilities:
Cancellation of debt income	8,118	8,118
Total deferred tax liabilities	8,118	8,118
Net deferred tax assets