See: http://www.irs.gov/Businesses/Gifts-from-Foreign-Person
Second, a better solution, to avoid reporting requirement and future divorce issues, it is recommended this money is a loan from your parents to you. All you need to do is to google "promissory note California" and download a form and fill in your name (borrower), your parent's name (lender), and 0% interest. In that case, your parents gift to you is 0% interest, Let's say market interest is 4%, your parent's gift to you is annually $4000 on a $100,000 loan).
This way, you don't have IRS reporting requirement, and in the future the money will be your parents (and yours) regardless your marriage situation, or in case that you die before your parents and your wife without a will.
Consult a lawyer on these issues is worthwhile, esp. combine this issue with the wills of your parents for a complete solution.