Dave Gilboa and Neil Blumenthal met while getting their MBAs at Wharton. They cofounded a glasses retailer, Warby Parker, and couldn't decide who should become CEO, so they both took the job. The Co-CEOs sat down with Business Insider's US Editor in Chief Alyson Shontell to discuss how they built a billion-dollar brand, and how they scaled the company as first-time founders.