7. Common Stock (Details 2) (Employee Stock Option [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Stock Option [Member]
Balance of employee stock options outstanding	3,457,500	3,266,500	3,000,500
Stock options granted	370,000	273,000	401,000
Stock options exercised	(390,000)	68,500	(60,000)
Stock options forfeited	(2,500)	13,500	(75,000)
Balance of employee stock options outstanding	3,435,000	3,457,500	3,266,500