Income Taxes (Details Textuals) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Loss carryforwards - federal	$ 52,580	$ 44,076
Loss carryforwards - state	37,175	43,270
Enhanced oil recovery credit carryforwards	48,900
Research and development credits	21,600
Tax credit carryover	34,837	34,837
Tax benefit not recorded to additional paid-in capital	15,700
Deferred Tax Assets, State Taxes	34,500
Deferred Tax Assets, Valuation Allowance	(33,600)	$ 0
Unrecognized Tax Benefits	$ 5,400