Exercise price per share or per unit of warrants or rights outstanding.

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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

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Number of warrants or rights outstanding.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Convertible Senior Notes - Schedule of Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Nov. 30, 2013
Debt Instrument [Line Items]
Proceeds	$ 0	$ 0	$ 54,071
2022 Warrants
Debt Instrument [Line Items]
Proceeds	$ 54,071
Shares (in shares)	5,807,000
Strike Price (in USD per share)	$ 203.40
Shares as of December 31, 2019 (in shares)				5,807,000
2018 Warrants
Debt Instrument [Line Items]
Proceeds	$ 84,525
Shares (in shares)					7,783,000
Strike Price (in USD per share)	$ 107.46
Shares as of December 31, 2019 (in shares)	0