Look, I do also feel bullish about the future of Tesla. However, a company does need to be profitable. And Tesla has proven that they cannot be profitable even with delivering the expected amount of Model 3's. At the same time, the incentives payments from various governments all over the world are ending this year or next year (USA, Germany, etc.), which will just put more pressure on Tesla.
The real question is: Can Tesla be profitable? And if yes, how profitable will they be? The stock market normally pays around a P/E multiple of 10-15 for carmakers and 15-30 for tech-companies. As Tesla is kind of a mixed company, I'd consider a P/E of 20 to be reasonable.
So if they achieve a yearly profit (EPS) of 10$ (based on the adjusted earnings of 2.90$ in Q4 2018), that suggest a share price of 200$. This however, does not take into account the current growth of the company. Market does currently interpret that Tesla cannot hold the current growth rate and therefore the valuation went down significantly (paired with the increased default risk).
So based on al information above and IF Tesla can really be sustainable profitable like in Q4 2018, I'd assume a share price of 250 - 350$ to be reasonable.