Annual report pursuant to Section 13 and 15(d)

Note 1 - Organization and Summary of Significant Accounting Policies (Tables)

v3.8.0.1
Note 1 - Organization and Summary of Significant Accounting Policies (Tables)
12 Months Ended
Dec. 31, 2017
Notes Tables  
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
   
2017
   
2016
   
2015
 
Expected volatility
   
66%
-
79%
     
59%
-
75%
     
61%
-
64%
 
Weighted-average volatility
   
 
75%
 
     
 
60%
 
     
 
62%
 
 
Expected dividends
   
 
 
     
 
 
     
 
 
 
Expected term (in years)
   
5.0
-
6.0
     
5.0
-
6.0
     
5.1
-
6.3
 
Risk-free rate
   
1.8%
-
2.1%
     
1.2%
-
1.8%
     
1.5%
-
1.9%