Time is money. People are way more expensive than equipment. You gain more in terms of productivity/salary cost if they take the laptops home. Start by assuming the equipment is a lost cost that you're never getting back. If you're proven wrong then it's a nice extra.

To mitigate risk slightly you can prevent someone from taking the equipment home for the first few months of employment. New hires generally have to spend the first few months proving themselves before getting benefits like that.

As a founder - I take my machine home with me. But employees keep their machine at work.

It's a tough one. Obviously keeping machines at work improves security of code etc. So I would suggest that if you do allow devs to take laptops home then VPN's/internet security/admin access/encrypted harddrives etc are all in place to ensure the companies security.

As a summary you're risking both the physical equipment as well as the IP your company has. So you need to be careful.

If you're a small startup, your developers could probably be spending their time working on their own ideas just as easily as they chose to work for you. They're probably not going to steal your IP, and if they wanted to try, not being able to take the computer they work on home wouldn't stop them... your code base is probably small enough they could recreate it from scratch now they know how it works.

In addition, if your devs find their work so interesting they'll take it home and work in their limited discretionary time, that extra work could save your startup. It'll be the kind of work done by highly engaged smart people who are working in the one place they have complete control over and have made completely comfortable. And you're getting this for free.

Your developers are not six-year-olds. They are unlikely to damage your equipment or do something like get drunk and screw up your codebase (besides, you're using version control, right? ...Right?). And if you fear they are, you're either hiring the wrong people or you're too suspicious because you don't totally understand or respect them.

Hire people you trust and respect, and then have a little faith in their judgment.

If you don't want them to take MacBooks home, buy iMac instead. Why would you don't want your developers take them home?