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

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- Definition

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

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- Definition

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

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Face (par) amount of the original debt instrument that was repurchased.

+ References

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- Definition

Amount of cash inflow (outflow) from long-term debt supported by a written promise to pay an obligation.

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Nature of Business - Notes Payable (Details) - USD ($) $ in Thousands	1 Months Ended
	Aug. 31, 2019	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Aug. 12, 2019	Jun. 30, 2015
Convertible Senior Notes
Notes Payable
Net proceed received	$ 391,000
2.25% Convertible Senior Notes due 2022 \| Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued		$ 120,699	$ 120,699			$ 335,700
Stated interest rate (as a percent)	2.25%					2.25%
Fees and expenses						$ 11,700
Debt redeemed/repurchased	$ 215,000
0.75% Convertible Senior Notes due 2024 and 1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes
Notes Payable
Fees and expenses	9,000
0.75% Convertible Senior Notes due 2024 \| Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued	200,000	200,000	200,000		$ 200,000
Stated interest rate (as a percent)					0.75%
1.50% Convertible Senior Notes due 2026 \| Convertible Senior Notes
Notes Payable
Aggregate principal amount of notes issued	$ 200,000	$ 200,000	$ 200,000		$ 200,000
Stated interest rate (as a percent)					1.50%
8.375% Notes due 2026 \| Notes Payable
Notes Payable
Stated interest rate (as a percent)				8.375%