Sharebased payments (Details 7) - Nonemployee Common stock warrants - Service and performance conditions [Member] - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Expected life (years) | 3 years | |
| Dividend yield | ||
| Minimum [Member] | ||
| Expected life (years) | 2 months 30 days | |
| Dividend yield | ||
| Volatility | 127.00% | 141.00% |
| Risk-free interest rate | 1.50% | 1.50% |
| Maximum [Member] | ||
| Volatility | 143.00% | 144.00% |
| Risk-free interest rate | 1.60% | 1.60% |
| Expected life (years) | 1 year 29 days | |