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Equity Incentive Plans (Details) - Employee Stock Option [Member] - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Fair value of the company's common stock on date of grant $ 0.95 $ 0.54
Expected term 6 years 6 months 6 years 6 months
Risk free interest rate 2.92% 2.02%
Dividend yield $ 0 $ 0
Volatility 79.00% 79.00%
Fair value of options granted $ 0.68 $ 0.38