I’ve heard Cruz’s support is from a lot of individual donors (the same fervor there was for a candidate called Obama).
Except (let us not forget) that Obama's "individual donors" included an very large percentage who used his campaign's internet donation system - which disable all verification features that would detect illegal multiple donations, illegal foreign donations and donations under fictitious names.
That was true in 2008 & 2012 and was covered fully on FR (as listed on Google below):