Is Ambarella, Inc. overvalued or undervalued?

As of 30 August 2018, the valuation grade for Ambarella, Inc. moved from expensive to risky, indicating a shift in perception regarding its financial health. The company appears to be overvalued, as evidenced by its Price to Book Value of 3.97 and negative EV to EBIT and EV to EBITDA ratios of -18.03 and -23.62, respectively. Additionally, the latest ROCE and ROE figures of -35.47% and -17.86% further underscore the company's struggles.
In comparison to its peers, Ambarella's valuation ratios are notably less favorable; for instance, Tower Semiconductor Ltd. has a P/E ratio of 37.63 and an EV to EBITDA of 13.38, while Cirrus Logic, Inc. boasts a more attractive P/E of 17.26 and an EV to EBITDA of 11.14. Despite a strong one-year stock return of 53.35% compared to the S&P 500's 17.14%, the long-term performance over three and five years shows Ambarella lagging significantly behind the benchmark, with returns of 27.28% and 55.84%, respectively, compared to 70.41% and 96.61% for the S&P 500.