CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical)	Dec. 31, 2020	Dec. 31, 2019
1 Percent Convertible Senior Notes [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Interest rate on convertible senior notes	1.00%	1.00%
0.125 Percent Convertible Senior Notes [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Interest rate on convertible senior notes	0.125%	0.125%

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120391452&loc=d3e13212-122682

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant