7. Common Stock (Details 3) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Non-vested stock options outstanding, beginning	721,836	749,835	791,668
Non-vested stock options granted	529,500	415,000	410,500
Non-vested stock options vested	(325,000)	(337,499)	(418,333)
Non-vested stock options forfeited	(195,000)	(105,500)	(34,000)
Non-vested stock options outstanding, ending	731,336	721,836	749,835