Tandem Diabetes Care Inc.(TNDM) popped 11% to $27.56 Tuesday on 3.8 million shares traded, a day after the insulin pump maker reported positive second-quarter financial results. The stock has been in a very steep and orderly up-channel from its low near $2 in February. A break through recent highs at $28.90 could take the stock into the mid-$30s next.