Common Shares Reserved for Issuance - Schedule of Reserved Shares of Common stock for Issuance (Details) - shares shares in Thousands	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	56,855	41,562
Convertible Senior Notes
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	15,141	0
Reserved under stock award plans
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	38,500	38,879
ESPP
Class of Stock [Line Items]
Shares reserved for future issuance (in shares)	3,200	2,700