The US State Department issued a Level 3 travel advisory cautioning citizens to reconsider visiting Turkey due to terrorism and arbitrary detentions.
As the official advisory notes on the website:

Reconsider travel to Turkey due to terrorism and arbitrary detentions. Some areas have increased risk. Read the entire Travel Advisory.
Do not travel to:
• Areas near the Syria and Iraq borders due to terrorism and kidnapping.
Terrorist groups continue plotting possible attacks in Turkey. Terrorists may attack with little or no warning, targeting tourist locations, transportation hubs, markets/shopping malls, local government facilities, hotels, clubs, restaurants, places of worship, parks, major sporting and cultural events, educational institutions, airports, and other public areas. Terrorists have also previously targeted Western tourists and expatriates.
Security forces have detained tens of thousands of individuals, including U.S. citizens, for alleged affiliations with terrorist organizations based on scant or secret evidence and grounds that appear to be politically motivated. U.S. citizens have also been subject to travel bans that prevent them from departing Turkey. Participation in demonstrations not explicitly approved by the Government of Turkey, as well as criticism of the government, including on social media, can result in arrest.
The U.S. government has very limited ability to provide emergency services to U.S. citizens traveling in Batman, Bingol, Bitlis, Diyarbakir, Gaziantep, Hakkari, Hatay, Kilis, Mardin, Sanliurfa, Siirt, Sirnak, Tunceli, and Van, as the U.S. government restricts its employees from traveling to specific provinces in these regions without prior approval.

If you decide to travel to Turkey:
• Stay alert in locations frequented by Westerners.
• Avoid demonstrations and crowds.
• Stay at hotels with identifiable security measures.
• Monitor local media and adjust your plans based on new information.
• Visit our website for Travel to High-Risk Areas.
• Enroll in the Smart Traveler Enrollment Program (STEP) to receive Alerts and make it easier to locate you in an emergency.
• Follow the Department of State on Facebook and Twitter.
• Review the Crime and Safety Report for Turkey.
• U.S. citizens who travel abroad should always have a contingency plan for emergency situations. Review the Traveler’s Checklist.