What was the change in the Property and equipment, net from 2018 to 2019?
{"December 31, -- ": {"2019": 2019, "2018": 2018}, "December 31, -- Computer equipment and purchased software": {"2019": 3011, "2018": 3167}, "December 31, -- Machinery and equipment": {"2019": 699, "2018": 821}, "December 31, -- Furniture and fixtures": {"2019": 1115, "2018": 1113}, "December 31, -- Leasehold improvements (1)": {"2019": 3897, "2018": 3897}, "December 31, -- Total": {"2019": 8722, "2018": 8998}, "December 31, -- Less accumulated depreciation and amortization (1)": {"2019": -7496, "2018": -6655}, "December 31, -- Property and equipment, net": {"2019": 1226, "2018": 2343}}
property_2019 = df["December 31, -- Property and equipment, net"]["2019"]
property_2018 = df["December 31, -- Property and equipment, net"]["2018"]
answer = property_2019 - property_2018