Quoting from this article,"Hacking TouchID relies upon a combination of skills, existing academic research and the patience of a Crime Scene Technician.

It is certainly not something your average street thief would be able to do, and even then, they would have to get lucky. Don’t forget you only get five attempts before TouchID rejects all fingerprints requiring a PIN code to unlock it. However, let’s be clear, TouchID is unlikely to withstand a targeted attack. A dedicated attacker with time and resources to observe his victim and collect data, is probably not going to see TouchID as much of a challenge. Luckily this isn’t a threat that many of us face.

TouchID is not a “strong” security control. It is a “convenient” security control. Today just over 50 percent of users have a PIN on their smartphones, and the number one reason people give for not using the PIN is that it’s inconvenient. TouchID is strong enough to protect users from casual or opportunistic attackers (with one concern I will cover later on) and it is substantially better than nothing."