Investors should tread very carefully with these stocks.Investors should be wary when it comes to cash-burning companies. These are businesses that aren't generating positive cash flow from their day-to-day operations. Not only does that mean their operations aren't sustainable, but it might mean their future survival depends on new sources of funding. That includes new share offerings, which dilute investors and send stock prices crashing.Three cash-burning stocks that are particularly concerning are Canop ...