Item 6. SELECTED FINANCIAL DATA

The following unaudited selected consolidated financial data are derived from our audited consolidated financial statements. These data should be read in conjunction with our audited consolidated financial statements and related notes that are included elsewhere in this Annual Report on Form 10-K and with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in Item 7.

(1) Total costs and expenses included (i) in 2017, an intangible asset impairment charge of $255.3 million, and (ii) in 2020, 2019, 2018 and 2017, collaborative license and asset acquisition expenses of $184.6 million, $318.3 million, $111.9 million and $168.7 million, respectively. See Note B, “Collaborative Arrangements.”

(2) In 2018, we released the valuation allowance on the majority of our net operating losses and other deferred tax assets resulting in a benefit from income taxes of $1.56 billion in the fourth quarter of 2018 and we recorded a $1.50 billion deferred tax asset on our consolidated balance sheet as of December 31, 2018. In 2020 and 2019, we began recording a provision for income taxes on our pre-tax income approximating statutory rates. In 2020, our provision for income taxes included discrete tax benefits associated with the $209.0 million transfer of intellectual property rights to the U.K., the write-off of a long-term intercompany receivable, and an increase in the U.K.’s corporate tax rate. See Note O, “Income Taxes.” In 2017, we recorded a benefit from income taxes related to the impairment of an intangible asset.