Quarterly report pursuant to Section 13 or 15(d)

Equity Incentive Plan (Details Textual)

v3.19.1
Equity Incentive Plan (Details Textual) - USD ($)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Jul. 10, 2018
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized $ 1,358,000 $ 945,000    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 2 years 2 months 8 days 1 year 6 months 25 days    
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding And Exercisable Intrinsic Value $ 0 $ 0    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 750,000 275,500    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights In general, options granted under the 2014 Plan vest with respect to one-third of the underlying shares on the one-year anniversary of the grant date and the remainder ratably over a 24-month period.      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized       891,222
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value   $ 151,200    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value $ 0.47 $ 0.55    
Share-based Compensation Arrangement by Share-based Payment Award, Description Incentive stock options may be granted to any officer or employee at an exercise price per share of not less than the fair value per common share on the date of the grant (not less than 110% of fair value in the case of holders of more than 10% of the Company’s voting stock) and with a term not to exceed ten years from the date of the grant (five years for incentive stock options granted to holders of more than 10% of the Company’s voting stock).      
Equity Incentive Plan 2014 [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 8,390,123      
Equity Incentive Plan 2014 [Member] | Maximum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant     8,390,123  
ESPP [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 117,090      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized 170,567      
2014 Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 4,033,056      
Excess Stock, Shares Authorized     350,000