XML 64 R48.htm IDEA: XBRL DOCUMENT v3.19.1
Stockholders' Equity And Stock-Based Compensation (Schedule Of Fair Value Of Employee Stock Options) (Details)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Options outstanding [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term in years     6 years 1 month 6 days
Expected volatility 70.00%   80.00%
Options outstanding [Member] | Minimum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term in years 5 years 3 months 18 days 4 months 24 days 6 years 1 month 6 days
Expected volatility   70.00% 80.00%
Risk-free interest rate 2.60% 1.00% 1.20%
Options outstanding [Member] | Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term in years 6 years 1 month 6 days 6 years 1 month 6 days  
Expected volatility   90.00%  
Risk-free interest rate 3.00% 2.20% 1.50%
2017 Employee Stock Purchase Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected volatility 70.00% 95.00%  
2017 Employee Stock Purchase Plan [Member] | Minimum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term in years 6 months 6 months  
Risk-free interest rate 1.90% 1.10%  
2017 Employee Stock Purchase Plan [Member] | Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected term in years 1 year 1 year 3 months 18 days  
Risk-free interest rate 2.50% 1.20%