Annual report pursuant to Section 13 and 15(d)

Income Taxes (Details Textual)

v3.19.1
Income Taxes (Details Textual) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Income Tax Disclosure [Line Items]      
Operating Loss Carry Forwards Expiration Year 2038    
Operating Loss Carryforwards $ 8,800,000    
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount $ 200,000 $ 24,400,000 $ 4,400,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent 21.00% 35.00%  
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount $ 0 $ 32,609 $ 0
Operating Loss Carry forwards Not Subject To Expiration $ 7,500,000    
Operating Loss Carryforwards, Limitations on Use $7.5 million which do not expire but are subject to 80% taxable income limitations    
California Franchise Tax Board [Member]      
Income Tax Disclosure [Line Items]      
Operating Loss Carry Forwards Expiration Year 2038    
Operating Loss Carryforwards $ 107,800,000    
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]      
Income Tax Disclosure [Line Items]      
Operating Loss Carry Forwards Expiration Year 2037    
Operating Loss Carryforwards $ 256,100,000    
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]      
Income Tax Disclosure [Line Items]      
Tax Credit Carryforward, Amount $ 9,000,000