CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	51,576,442	51,676,140
Common stock, shares outstanding	51,576,442	51,676,140