Debt (Tables)

3 Months Ended

Mar. 31, 2017

Debt Disclosure [Abstract]

Convertible Debenture Terms

The following table summarizes at March 31, 2017 the related balances, conversion rate and conversion price of the Debentures:

Outstanding principal amount	$	512.6
Unamortized debt discount	$	172.5
Net debt carrying amount	$	334.4
Equity component carrying amount	$	185.8
Conversion rate (shares of common stock per $1,000 of principal amount)	13.6666
Effective conversion price (per $1,000 of principal amount)	$	73.1704