Mattel, Inc., designs, manufactures, and markets toy products worldwide. Mattel’s toys include Barbie^TM fashion dolls and accessories, Hot Wheels^TM, and Fisher-Price brands. For a recent year, Mattel reported the following net cash flows from operating activities (in thousands):

First quarter ending March 31                                    $ (326,536)

Second quarter ending June 30                                    (165,047)

Third quarter ending September 30                             (9,738)

Fourth quarter December 31                                        1,243,603

Explain why Mattel reports negative net cash flows from operating activities during the first three quarters, yet reports positive cash flows for the fourth quarter and net positive cash flows for the year.