Top analyst Toni Sacconaghi on his concerns about Tesla's valuation

Tesla began deliveries of its new Model S Plaid, a high-performance version of the company’s flagship electric sedan, on Thursday with a livestream event at the company’s test track near its factory in Fremont, California. Toni Sacconaghi, Bernstein senior research analyst who covers U.S. IT hardware, joined "Squawk Box" on Friday to discuss.