XML 50 R40.htm IDEA: XBRL DOCUMENT v3.19.1
Note 9 - Stockholders' Equity - Valuation Assumptions (Details) - Share-based Payment Arrangement, Option [Member]
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Risk-free interest rate 2.50% 2.60%
Dividend yield 0.00% 0.00%
Volatility 68.80% 71.40%
Expected life (Year) 6 years 6 years