Canopy Growth (CGC 2.87%) is a Canadian marijuana company. When it first came public marijuana was a hot sector, but investor enthusiasm has waned. The stock has since declined to the point where it is a penny stock, trading around the $1 per share mark. That's the big-picture backdrop for the recent 25% price gain, but there's a lot more to understand before you consider investing in this company.Canopy Growth's rally isn't as huge as it looksPenny stocks are generally high-risk investments that most inves ...