Hi, Sean.
What other requirements do you need aside from input of the op amp which is -2V to 1V? Do you need single supply op amp or dual supply op amp? Where will the Vout=Vref-Vdet go or what is its next stage? We have to consider the voltage range of the output of the op amp in order to match this with the next stage. Does the next stage needs large input voltage (meaning the op amp should have large gain) or small input voltage? Does the next stage needs a clean signal (meaning the op amp should have low offset and low noise)?
Please provide more details of your circuit.
Regards,
Anna