Annual report pursuant to Section 13 and 15(d)

Note 1 - Organization and Summary of Significant Accounting Policies - Assumptions Used to Calculate Fair Value of Stock Option Awards Granted (Details)

v3.8.0.1
Note 1 - Organization and Summary of Significant Accounting Policies - Assumptions Used to Calculate Fair Value of Stock Option Awards Granted (Details)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Expected volatility 66.00% 59.00% 61.00%
Expected volatility 79.00% 75.00% 64.00%
Weighted-average volatility 75.00% 60.00% 62.00%
Expected dividends
Risk-free rate 1.80% 1.20% 1.50%
Risk-free rate 2.10% 1.80% 1.90%
Minimum [Member]      
Expected term (Year) 5 years 5 years 5 years 36 days
Maximum [Member]      
Expected term (Year) 6 years 6 years 6 years 109 days