Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Details)

v3.6.0.2
Income Taxes - Additional Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Operating Loss Carryforwards [Line Items]      
Income tax expense $ 0 $ 0 $ 0
Federal statutory income tax rate 34.00% 34.00% 34.00%
Increase in the valuation allowance $ 8,200,000 $ 19,600,000 $ 29,900,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate 7,000,000    
Accrued interest or penalties related to uncertain tax positions 0    
Stock Option [Member]      
Operating Loss Carryforwards [Line Items]      
Net Operating Loss Carry-forwards 5,200,000    
State [Member]      
Operating Loss Carryforwards [Line Items]      
Net Operating Loss Carry-forwards $ 196,000,000    
Net operating loss carryforwards expiration year 2017    
California [Member]      
Operating Loss Carryforwards [Line Items]      
Net operating loss carry-forward expired $ 41,200,000 22,400,000 54,300,000
Federal [Member]      
Operating Loss Carryforwards [Line Items]      
Net Operating Loss Carry-forwards $ 335,900,000    
Net operating loss carryforwards expiration year 2018    
Net operating loss carry-forward expired $ 0 $ 0 $ 0