v3.20.2

Convertible Senior Notes - Additional Information (Details) shares in Millions	3 Months Ended			6 Months Ended
	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 shares	Jun. 30, 2020 USD ($) day trading_day shares	Jun. 30, 2019 shares	Dec. 31, 2019 USD ($)	Jun. 30, 2017 USD ($)	Nov. 30, 2013 USD ($)
Debt Instrument [Line Items]
Percentage of purchase price of notes which should be paid upon fundamental change (percent)				100.00%
Benefit from exercise of 2022 Note Hedge		$ 18,312,000		$ 21,864,000
Estimated fair value of the note based on the closing trading price		$ 100		$ 100		$ 100
Warrant exercise period | trading_day				60
2022 Warrants
Debt Instrument [Line Items]
Number of potential securities issued upon automatic exercise of the Warrants (in shares) | shares		2.9		2.9
2018 Warrants
Debt Instrument [Line Items]
Number of shares to be issued upon exercise of the Warrants (in shares) | shares			1.6		4.3
Stock Price Trigger Measurement
Debt Instrument [Line Items]
Trading days threshold | day				20
Consecutive trading days threshold, total | day				30
Threshold percentage of stock price trigger (percent)				130.00%
Notes Price Trigger Measurement
Debt Instrument [Line Items]
Trading days threshold | day				5
Consecutive trading days threshold, total | day				5
Threshold percentage of stock price trigger (percent)				98.00%
Conversion of notes base conversion price				$ 1,000
2022 Notes
Debt Instrument [Line Items]
Face amount of debt		$ 764,778,000		764,778,000		$ 782,491,000	$ 782,500,000
Stated interest rate							0.00%
Cash paid for settlement of debt				18,000,000
Fair value adjustments				23,000,000
Benefit from exercise of 2022 Note Hedge				$ 22,000,000
Remaining discount amortization period				23 months
2022 Notes | Forecast
Debt Instrument [Line Items]
Cash paid for settlement of debt	$ 23,000,000
2018 Notes
Debt Instrument [Line Items]
Face amount of debt								$ 575,000,000
Stated interest rate								0.00%

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