Piper Sandler analyst Christopher Raymond named Ardelyx a top small cap pick for 2020 despite the stock's strong 2019. The analyst highlights continued positive nephrologist feedback regarding the company's lead drug tenapanor. Both nephrologists and renal dieticians highlight a significant unmet need in phosphorus control, high awareness and anticipation of commercial availability of tenapanor, and an increasing view that tenapanor will be used first-line, Raymond tells investors in a research note. He believes Ardelyx shares could double and keeps an Overweight rating on the name with a $15 price target.