Is Navidea Biopharmaceuticals, Inc. overvalued or undervalued?

As of 8 August 2019, the valuation grade for Navidea Biopharmaceuticals, Inc. moved from risky to does not qualify, indicating significant concerns regarding its financial health. The company is currently assessed as overvalued, primarily due to its negative price-to-book value of -0.02 and an EV to EBITDA ratio of 0.25, which suggests that the company is not generating sufficient earnings relative to its enterprise value. Additionally, the return on capital employed (ROCE) is exceptionally high at 173.19%, but this figure is misleading given the company's overall financial instability.
In comparison with peers, Navidea's valuation metrics are concerning. For instance, BioRestorative Therapies, Inc. has a worse EV to EBITDA ratio of -0.3148, while Ekso Bionics Holdings, Inc. shows a risky valuation with an EV to EBITDA of -0.7257. The stock has significantly underperformed against the S&P 500 over various periods, notably a 71.43% decline in the past week, reinforcing the notion that it is overvalued given its current financial state and market performance.