CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	Mar. 31, 2018	Mar. 31, 2017
Convertible Senior Notes 0.375 Percent Due 2018
Interest rate of debt (as a percent)	0.375%	0.375%
Convertible Senior Notes 1.25 Percent Due 2020
Interest rate of debt (as a percent)	1.25%	1.25%

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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