8. Common Stock (Details 2) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock options granted	410,500
Stock options forfeited	(34,000)
Employee Stock Option [Member]
Balance of employee stock options outstanding	2,957,667	2,657,667	3,435,000
Stock options granted	410,500	395,000	410,000
Stock options exercised	0	(20,000)	(877,333)
Stock options forfeited	(34,000)	(75,000)	(310,000)
Balance of employee stock options outstanding	3,334,167	2,957,667	2,657,667