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7. Shareholders' Equity (Details - Assumptions)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Equity [Abstract]      
Expected life (years) 3 years 11 months 26 days 4 years 7 days 4 years 15 days
Risk-free interest rate 2.74% 1.59% 1.09%
Volatility 34.00% 36.00% 51.00%
Expected dividend yield 0.00% 0.00% 0.00%