1. A system comprising: a hardware processor; and a memory device coupled to the processor, the memory device comprises a parser that, when executed by the hardware processor, examines one or more portions of a Portable Document Format (PDF) document to determine if one or more suspicious characteristics indicative of malicious network content are included in the one or more examined portions of the PDF document, wherein the one or more examined portions of the PDF document comprise less than an entirety of the PDF document, and one or more virtual machines to receive the PDF document in response to the one or more examined portions of the PDF document being determined to include one or more suspicious characteristics indicative of malicious network content, the one or more virtual machines to process at least the one or more examined portions of the PDF document so as to determine whether the PDF document includes malicious network content.