The DCF valuation for VOC would not be nil or negative unless...

The DCF valuation for VOC would not be nil or negative unless the investments made in the early growth period did not generate a (satisfactory) return at some point in the future. Growth companies have a valuation because investors forecast that further down the track the growth period will end and a much higher amount of cash flow will be distributed to them (ie. dividends, share buy backs, capital return). It may take a long time for this to happen, and you definitely need to account for this in your valuation if this is the case.

An alternative to DCF may be found in a book called Franchise Value by Leibowitz.

http://www.amazon.com/Franchise-Value-Approach-Security-Analysis/dp/0471647888