Equity (Tables)

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Class of treasury stock

The table below summarizes the shares of our Common Stock we repurchased under the program and the cost of the shares received, which were recorded as Treasury Stock.

	Year Ended December 31,
	2020		2019
Number of shares repurchased	1,605,582		722,596
Total cost of shares received	$	746.0	$	254.0

The table below summarizes the shares of our Common Stock Sanofi elected to sell, and we elected to purchase, to satisfy Sanofi's funding obligations and the cost of the shares received, which were recorded as Treasury Stock.

	As of December 31,
	2020		2019		2018
Libtayo:
Number of shares purchased (by issuing a credit towards the amount owed by Sanofi)	77,677		210,733		215,387
Total cost of shares received	$	41.7	$	73.3	$	75.8
Dupilumab/Itepekimab:
Number of shares purchased (in cash)	171,471		93,286		10,766
Total cost of shares received	$	93.3	$	29.4	$	4.4