CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Stockholders' equity:
Convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, Authorized shares	5,000,000	5,000,000
Convertible preferred stock, Issued shares	0	0
Convertible preferred stock, outstanding shares	0	0
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, Authorized shares	500,000,000	500,000,000
Common Stock, Issued shares	109,287,591	115,161,675
Common Stock, outstanding shares	109,287,591	115,161,675