Escrow service for one project with ICO is needed

[superzebra]

I would possibly launch some pre ICO and ICO later to fund my startup.

But seeing a number of failing startups I want to find reliable escrow service which will allow investors invest only when they are sure that stages of the project are complete.

For example, i ask investors for sum X.
But I only get money from escrow if I can show it if I reached X amount of sales or my product now have this or this feature.

This will allow escrow to return part of money to investors if we as project failed, and what is also important - it will keep money as cryptocurrencies - so if value will be growing at same time investors can extract it without losing this grow.

What do you think - is this kind of escrow exits? Maybe just split investments into smaller parts? so investors will be called on every stage (every 2 weeks for example?)

What do you think?