Actually, as a California employee, you are protected by The California Family Rights Act (CFRA) (the state equivalent of FMLA) and the Fair Employment and Housing Act (FEHA) (the state equivalent of the ADA) in addition to the FMLA and ADA. Generally, California laws provide greater protections to employees than their federal counterparts, and as a California employee, you are entitled to protection under the law that gives you the greatest rights.
Under California law, if your medical condition qualifies as a disability under the (FEHA) (which I suspect it does, given that it has caused you to be unable to work for more than 12 weeks) your employer is required to reasonably accommodate your disability. A leave of absence is one type of reasonable accommodation. There is no specific length of time that is reasonable for a medical leave under the FEHA. Rather, the employer must have a conversation with you about how much more time off you need and make a determination whether providing you the additional time off requested will pose an undue hardship on the company. If it will not pose an undue hardship on the company to give you the additional time off, then the employer must give you the time off.
It is important to note that if you are taking your medical leave under CFRA/FMLA, your employer CANNOT simply fire you once your 12 weeks are up. Rather, the employer must have a conversation with you about how much more time you need and make a determination whether providing you the additional time off requested will pose an undue hardship on the company.
However, you are not entitled to an INDEFINITE leave either. Thus, for example, if your doctor provides a note to your employer which states that you may NEVER be able to return to work, the company may legally be able to fire you.
If your employer violates the law, please give us a call at (213) 536-4236, email us at info@sarnofflaw.com, or fill in an online questionnaire at www.sarnofflaw.com.