idle time and user time as negative value?

I'm monitoring the CPU usage of my NodeJS application by the means of the os.cpus() function. When printing the return values of the function, I noticed some cores show negative values for user time and idle time. Is that even possible?

Edit:

Here is one of the CPUs in the returned object of that function call.

{ model: 'Intel(R) Xeon(R) CPU           E7540  @ 2.00GHz',
    speed: 1064,
    times: { 
        user: -599586196,
        nice: 46900,
        sys: 726751700,
        idle: -1356274912,
        irq: 1000 
    } 
},