Mattel, Inc. designs, manufactures, and markets toy products worldwide. Mattel's toys include Barbie™ fashion dolls and accessories, Hot Wheels™, 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, 2005 ......... $(374,933)
Second quarter ending June 30, 2005 ........ (551,080)
Third quarter ending September 30, 2005 ........ (629,006)
Year ending December 31, 2005 .......... 466,677
Explain how Mattel can report negative net cash flows from operating activities during the first three quarters yet report net positive cash flows on December 31.