If you can't already cover your own living expenses for a while, go work for a decent salary for a year or two. You're probably early in your career, so you'll get valuable experience, and if you're single and frugal, should have more than enough in a savings account at the end to live for 3-6 months. And you can spend some nights and weekends developing your idea while you're at it[1].

[1] Well, assuming California. Other places there may be issues with moonlighting. Make sure you know local laws and read what you signed when you were hired.