I work for a California company remotely from home in another state. I spent a few days on a business trip to HQ in San Francisco. Do I owe income tax to California?

Yes, you have to file a CA income tax return. 

Per CA Department of Revenue: You are required to file a Nonresident or Part-Year Resident Income Tax Return (Long or Short Form 540NR) with California if you have income from California sources.

Compensation: Wages and salaries have a source where the services are performed. The source of this income is not affected by either of the following:

• The location of the employer where the payment is issued
• Your location when you receive payment
• Nonresidents of California are Taxed only on income from California sources.

Related information:

• How do I file a nonresident state return?

Thank you for your answer. Is there a threshold below which I don't need to file? I basically started there mid-December and the two weeks I spent in HQ were the only two weeks I had income in California from that company.

No, there is not threshold like some states have. CA want's every penny they could get. Good luck!

Thank you!