What was the change in the Beginning balance from 2018 to 2019?
{"": {"2019": "(in thousands)", "2018": ""}, "Beginning balance": {"2019": 240500, "2018": 310645}, "Other additions": {"2019": 86, "2018": "\u2014"}, "Transfers to developed technology from IPR&D": {"2019": 4400, "2018": "\u2014"}, "Amortization": {"2019": -57015, "2018": -67947}, "Impairment losses": {"2019": "\u2014", "2018": -2198}, "Ending balance": {"2019": 187971, "2018": 240500}}
beginning_balance_2019 = df["Beginning balance"]["2019"]
beginning_balance_2018 = df["Beginning balance"]["2018"]
answer = beginning_balance_2019 - beginning_balance_2018