If your "place of work" is going to be in the US, you fall under the employment laws of the US and the state in which you reside. It doesn't really matter where your employer is headquartered or located, except when it comes to the precise manner in which you are paid and how you pay your taxes and withholdings.

If you're an employee, the company will have to do all the usual withholdings and remit them to the governments (Federal and State) through some US entity (branch, subsidiary, etc.). If they don't have a US presence other than you, they'll probably pay you as a contractor, in which case you become responsible for filing all the necessary taxes and withholdings.

Staying in Hong Kong for 2 to 3 months a year doesn't "break" your US residence. It's considered a business trip - which may result in some deductible business expenses, depending on how your employer handles things.
Cheers,
Bev