7. Common Stock (Details 2) - Employee Stock Option [Member] - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Balance of employee stock options outstanding	3,435,000	3,457,500	3,266,500
Stock options granted	410,000	370,000	273,000
Stock options exercised	(877,333)	(390,000)	(68,500)
Stock options forfeited	(330,000)	(2,500)	(13,500)
Balance of employee stock options outstanding	2,637,667	3,435,000	3,457,500