Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Equity Incentive Plans) (Narrative) (Details)

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Stockholders' Equity (Equity Incentive Plans) (Narrative) (Details) - shares
1 Months Ended 12 Months Ended
Jun. 30, 2018
Dec. 31, 2020
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Predetermined offering period, lower fair market value percentage   85.00%  
Number of shares purchased under ESPP   140,856  
Shares available for future sale under ESPP   259,144  
Stock Options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares authorized 5,000,000   2,000,000
Expiration period     10 years
Additional shares authorized 3,000,000    
Shares available for grant   1,180,085