Note K - Stock-based Compensation - Black-Scholes Option Pricing Model (Details) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Expected dividend yield | 0.00% | 0.00% | 0.00% |
| Minimum [Member] | |||
| Risk-free interest rate | 1.29% | 1.40% | 0.91% |
| Expected term (in years) (Year) | 5 years 182 days | 4 years 120 days | 7 years |
| Expected volatility | 77.38% | 68.79% | 86.00% |
| Maximum [Member] | |||
| Risk-free interest rate | 1.50% | 1.99% | 2.70% |
| Expected term (in years) (Year) | 6 years 94 days | 6 years 91 days | 10 years |
| Expected volatility | 94.78% | 86.84% | 95.00% |