[gibwell]

They sell millions of licenses a year. Their revenue per employee exceeds that of Google or Apple.

Is more explanation needed?

[sgustard]

Do you have a source for those numbers? I have no reason to doubt you, but you seem put off by the question. It's a legitimate concern before sending money to a company to ask how financially secure they are.

[gibwell]

I was put off by the idea they needed a business model other than selling the app for money.

A little googling should provide the due diligence you require.