What is the change in the weighted-average common shares for basic and diluted net loss per share between 2017 and 2018?
{"Numerator -- Net loss": {"2019": -53607.0, "2018": -26203.0, "2017": -4204.0}, "Denominator -- Weighted-average common shares for basic and diluted net loss per share": {"2019": 83130.0, "2018": 79500.0, "2017": 76281.0}, "Denominator -- Basic and diluted net loss per share": {"2019": -0.64, "2018": -0.33, "2017": -0.06}}
denominator_2018 = df["Denominator -- Weighted-average common shares for basic and diluted net loss per share"]["2018"]
denominator_2017 = df["Denominator -- Weighted-average common shares for basic and diluted net loss per share"]["2017"]
answer = denominator_2018 - denominator_2017