Every ballot has been counted in every California county, but two. There may be 258 ballots left in Sutter county and there may be 6,000+ in Lake County. Lake County is a small 65,000 person county with less than 34,000 registered voters. They reported 9,703 ballots on election day and haven't reported since. Some counties don't issue reports after every day of contend and wait to report to the Secretary of State when they finish counting. Even then, it appears Lake County wants to wait until the deadline, which isn't until next week. I don't know why. If they really have 6,000 valid ballots, they will be among the highest turn-out counties with more than 10,000 registered voters.
As of now, Betty Yee leads John Perez 877,117 to 876,268, an 849 vote lead. Even if there are 6,000 valid ballots in Lake County, there shouldn't be a big enough difference in votes to put Perez ahead. if things break right he could gain 400-500 votes, however. Right now the results are Yee 21.75% to Perez 21.73%. A candidate often requests a recount if the race is closer than 0.5%. This race is 0.02%. There'll be a recount and I'd expect the lead to change during one.
Edit: Sutter county is in. John Perez gained 12 votes on Betty Yee, cutting her lead to 837 votes. There's only one county left to count. When they'll count is anyone's guess.