Income Taxes (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Income Taxes (Textual) [Abstract]
Percentage of uncertain income tax	0.5
Total liability for unrecognized tax benefits	$ 0
Accrual interest and/or penalties related to income tax	0	0
Unrecognized interest and/or penalties related to income tax	0	0
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Income tax net operating loss carryforwards	362,055,000
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Income Tax Disclosure [Line Items]
California research and development tax credit carryforwards	16,490,000
State and Local Jurisdiction [Member]
Income Tax Disclosure [Line Items]
Income tax net operating loss carryforwards	280,591,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Income Tax Disclosure [Line Items]
California research and development tax credit carryforwards	$ 10,283,000