Ok...for anyone else struggling with something similar, I figured out a way. There are probably more elegant ways to do this, but at least I was able to get over this hump this way:
fileID=fopen(filename,'r');
delimiter='\t';
formatSpec='%f%s%[^\n\r]';
dataArray = textscan(fileID, formatSpec, 'Delimiter', delimiter, 'ReturnOnError', false);
freq = dataArray{:, 1};
magNphase = dataArray{:, 2};
for i=1:length(magNphase)
splitmagNphase=strsplit(char(cellstr(magNphase{i})),',');
magtmp=erase(splitmagNphase{1},'(');
magtmp=erase(magtmp,'dB');
mag=[mag;str2num(magtmp)];
phtmp=erase(splitmagNphase{2},char(176));
phtmp=erase(phtmp,')');
ph=[ph;str2num(phtmp)];
end