Represents the percentage of aggregate principal amount payable in case of event of default.

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The percentage of principal amount of debt arrived at as the repurchase price under the debt conversion arrangement.

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Represents the number of business days immediately after any five consecutive trading day period during the debt instrument measurement period.

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Represents the number of consecutive trading days prior to the five consecutive business days during the debt instrument measurement period.

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Percentage of the trading price to the product of the sale price of the entity's common stock and the conversion rate

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The percentage of conversion premium above the last reported sale price of common stock.

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Represents number of days for which the company has remedy for an event of default relating to certain failures by the Company to comply with certain reporting covenants in the Indentures consists exclusively of the right to receive additional interest on the Notes.

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No definition available.

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Default payment, percentage of principal amount of notes

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Represents the debt instrument principal amount denomination for conversion into common stock.

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Represents the price at which the debt may be repurchased, as a percentage of the principal amount if the entity undergoes a change of control.

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No definition available.

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The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Remaining amortization period for discount on the liability component of convertible debt which may be settled in cash upon conversion, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

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No definition available.

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Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

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No definition available.

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Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

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Face (par) amount of debt instrument at time of issuance.

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Amount of the fee that accompanies borrowing money under the debt instrument.

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

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The cash outflow for a financial contract that meets the hedge criteria as either a cash flow hedge, fair value hedge, or hedge of a net investment in a foreign operation.

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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Price of a single share of a number of saleable stocks of a company.

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No definition available.

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Notes Payable - 0.75% Convertible Senior Notes Due 2024 and 1.50% Convertible Senior Notes Due 2026 (Details)				1 Months Ended		6 Months Ended
	Aug. 12, 2019 USD ($)	Aug. 07, 2019 USD ($) $ / shares	Apr. 15, 2019 USD ($) $ / shares shares	Aug. 31, 2019 USD ($) D	Jun. 30, 2015 USD ($) D $ / shares shares	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Notes Payable
Payments for convertible note hedges				$ 25,200,000	$ 21,100,000
Repurchase price				100.00%
The percentage of aggregate principal amount of notes outstanding and payable in case of event of default under the agreement.				25.00%
Default payment days						180 days
2.25% Convertible Senior Notes due 2022 \| Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued					335,700,000	$ 120,699,000	$ 120,699,000
Net proceed received					324,000,000.0
Fees and expenses					$ 11,700,000
Stated interest rate (as a percent)				2.25%	2.25%
Conversion rate, number of shares to be issued per			68.9172		60.3209
Principal amount used for debt instrument conversion ratio			$ 1,000		$ 1,000
Initial conversion price (in dollars per share) \| $ / shares			$ 14.51		$ 16.58
Shares issuable upon conversion of debt (in shares) \| shares			23,135,435		20,249,665
Number of trading days \| D					20
Consecutive trading days \| D					30
Minimum percentage of stock price					130.00%
Number of business days immediately after any five consecutive trading day period during the measurement period \| D					5
Number of consecutive trading days before five business days during the measurement period \| D					5
Repurchase price, as percentage of principal amount, if company undergoes change of control					100.00%
Amortization period					7 years
2.25% Convertible Senior Notes due 2022 \| Convertible Senior Notes \| Minimum
Notes Payable
Percentage of aggregate principal amount payable, in case of event of default					25.00%
2.25% Convertible Senior Notes due 2022 \| Convertible Senior Notes \| Maximum
Notes Payable
Percentage of the trading price to the product of the sale price of the entity's common stock and the conversion rate					98.00%
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes
Notes Payable
Net proceed received				$ 391,000,000.0
Fees and expenses				9,000,000.0
Conversion rate, number of shares to be issued per	74.6687
Principal amount used for debt instrument conversion ratio		$ 1,000		$ 1,000
Initial conversion price (in dollars per share) \| $ / shares		$ 13.39
Conversion premium percentage on sale price of common stock		37.50%
Share Price \| $ / shares		$ 9.74
Number of consecutive trading days before five business days during the measurement period \| D				5
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes \| Calendar quarter commencing after December 31, 2019
Notes Payable
Number of trading days \| D				20
Consecutive trading days \| D				30
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes \| Measurement period
Notes Payable
Number of business days immediately after any five consecutive trading day period during the measurement period \| D				5
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes \| Minimum \| Calendar quarter commencing after December 31, 2019
Notes Payable
Minimum percentage of stock price				130.00%
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes \| Maximum \| Measurement period
Notes Payable
Conversion premium percentage on sale price of common stock				98.00%
0.75% Convertible Senior Notes due 2024 \| Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued	$ 200,000,000.0			$ 200,000,000.0		200,000,000	200,000,000
Stated interest rate (as a percent)	0.75%
Amortization period				5 years
1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued	$ 200,000,000.0			$ 200,000,000.0		$ 200,000,000	$ 200,000,000
Stated interest rate (as a percent)	1.50%
Amortization period				7 years