[siberianbear]

I asked a California business attorney this question. She said that you really don't have that much protection. If your idea/company is valuable enough, your huge tech company employer will just sue you into oblivion. The legal costs alone will bury you. The specific California statute that protects what you do with your own time and resources doesn't protect you very much.

[drenvuk]

It's some protection, and there are niches that none of those tech companies have touched yet. I don't see why people don't see them. If it's a thought that should normally occur in your work day because it could related to your job description or company's products that you could reasonably have an impact on then you're not protected. If it's completely out of left field relative to the previous items then there's no way they could lay claim to it. How could they? Tech is much broader that a lot of people generally think about. Let's say you're doing front end work and your company is some social network but at night you have a brilliant idea for automating biological sample isolation using some robotic system you conjured up during a cup of hot cocoa on the weekend? How is the company going to even attempt to sue you for it when you used none of their resources, the idea was worked on during non-standard hours, and it has nothing to do with them?

If by tech you mean "along the same lines of what I'm doing at work" then you're gonna have a rough time. I do hope that your mind has the ability to wander a bit further from the train of thought you have you typically have while doing what you're paid for.

This goes for the other two replies above as well. If you have an original idea then you're safe. The hard part is having an original idea or even an idea that is several steps removed from a previous idea but still useful.