Debt (Tables)

9 Months Ended

Sep. 30, 2017

Debt Disclosure [Abstract]

Convertible Debenture Terms

The following table summarizes at September 30, 2017 the related balances, conversion rate and conversion price of the Debentures:

Outstanding principal amount	$	512.6
Unamortized debt discount	$	170.9
Net debt carrying amount	$	336.2
Equity component carrying amount	$	185.8
Conversion rate (shares of common stock per $1,000 of principal amount)	13.7223
Effective conversion price (per $1,000 of principal amount)	$	72.8735