CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	56,618,692	56,152,317
Common stock, shares outstanding (in shares)	55,246,262	54,860,883
Treasury stock (in shares)	1,372,430	1,291,434