Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Details)

v3.10.0.1
Income Taxes - Additional Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Operating Loss Carryforwards [Line Items]    
Income Tax Expense (Benefit) $ (100,000) $ 1,700,000
Increase (Decrease) in the valuation allowance $ 5,800,000 $ (166,100,000)
Federal statutory income tax rate 21.00% 34.00%
Operating Loss Carryforwards Offset of Taxable Income Percentage 80.00%  
Unrecognized tax benefits that would impact effective tax rate $ 4,500,000  
Accrued interest or penalties related to uncertain tax positions 0  
Federal Orphan Credit [Member]    
Operating Loss Carryforwards [Line Items]    
Tax credit carry forward amount $ 1,200,000  
Tax credit carryforward expiration year 2037  
State [Member]    
Operating Loss Carryforwards [Line Items]    
Net operating loss carry-forwards $ 39,100,000  
Net operating loss carryforwards expiration year 2033  
California [Member] | Research and Development [Member]    
Operating Loss Carryforwards [Line Items]    
Tax credit carry forward amount $ 19,800,000  
Federal [Member]    
Operating Loss Carryforwards [Line Items]    
Net operating loss carry-forwards $ 48,800,000  
Net operating loss carryforwards expiration year 2036