When a development stage biotechnology company receives a complete response letter (CRL) from the FDA, its shares almost always fall sharply, and its viability is called into question. But no company's viability can be determined on the basis of simply receiving a complete response letter. What matters is what is contained within that letter. And the contents of NuPathe's (PATH) complete response letter suggest that as the company heads into its resubmission PDUFA date, there is a buying opportunity for risk tolerant investors. For the record, unless otherwise noted, financial statistics and management commentary used in this article will be sourced from one of 3 places: the company's Q3 2012 conference call, its latest investor presentation...