Shares of Tandem Diabetes Care (NASDAQ: TNDM) were 10.9% higher as of 2:42 p.m. EDT on Thursday. Investors continued to drive up the insulin-pump maker's stock following Tandem's second-quarter update on Monday after the market closed. Tandem's share price has risen more than 27% since the company announced its Q2 results.There are three key reasons why investors are so excited about Tandem right now.