[DigiMortal]

I'd consider a few things:

What is the product/service that will generate revenue? - The "start up" is bringing that to the market - So they're developing, or working to get that product or product pipeline to the market - That can come in various stages, the company survives this developing stage through various funding (like that series A $) - I'd consider, are they generating revenue? margins are looking like? P&L / forecasting future sales revenue measuring with margins and profitability - Size really depends on what is going on, 50 people can mean several things...

So really, I'd consider it out of start up mode once there is a viable product that can be taken/sold in the market and bring in revenue.

I think once it's out there, once $ starts coming in, the company may still grow and hire more or expand and all that, but that's generally a good sign

My answer seems more vague now that I've read it, but its all about the $$$, healthy P&L, and forecasted revenue!