as the price of bitcoin was trading round about 660 USD before the bitfinex issue but after bitfinex issue people start panic selling of bitcoin and the price of bitcoin reach to 500 USD, and after that market recover its position and was trading below 600USD for a long time, i think the reason was just the confidence fo the people, people were not interested to invest their money in bitcon becasue of lack of confidence, but now people start using it its mean that they have not got confidence on bitcoin.