From Lugano Airport Agno (LUG) take a Taxi (10 minutes, 25-30 CHF).
From Zurich Airport (ZHR): take the train to Lamone-Cadempino (goes once per hour, very nice 3 hour trip through the Alps).
From Malpensa Airport (MXP): take the bus Malpensa Express to Lugano Station (roughly 80 min). Note that Malpensa is in Italy.
From Lugano station or Lamone-Cadempino to IDSIA, please see the section "How to reach us - Public transport".