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Income Taxes - Narrative (Details) (USD $)	12 Months Ended			65 Months Ended
Income Taxes - Narrative (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011 ownership	Aug. 31, 2006
Operating Loss Carryforwards [Line Items]
Income Tax Examination, Penalties and Interest Accrued	$ 0	$ 0
Income Tax Expense (Benefit)	84,000us-gaap_IncomeTaxExpenseBenefit	0us-gaap_IncomeTaxExpenseBenefit	5,000us-gaap_IncomeTaxExpenseBenefit
Unrecognized tax benefits	1,019,000us-gaap_UnrecognizedTaxBenefits	899,000us-gaap_UnrecognizedTaxBenefits	714,000us-gaap_UnrecognizedTaxBenefits
Number of changes in ownership				3
Valuation allowance	110,338,000	102,949,000
Total deferred tax assets	111,513,000us-gaap_DeferredTaxAssetsGross	104,119,000us-gaap_DeferredTaxAssetsGross
Income Tax Examination, Penalties and Interest Expense	0	0	0
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	211,200,000
Operating loss carryforwards decrease				121,100,000	1,900,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards decrease				53,329,000
State and Local Jurisdiction [Member] \| California [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	209,100,000
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 1,969,000