Convertible Senior Notes - Capped Call and Common Stock Forward (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended						3 Months Ended	12 Months Ended
	May 18, 2020	Nov. 30, 2020	Aug. 31, 2020	May 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2020	Jul. 01, 2020	May 29, 2020	Mar. 31, 2018
Capped Call and Common Stock Forward
Interest rate (as a percent)				3.50%
Share Price		$ 22.25	$ 10.25		$ 2.75		$ 2.35
Common stock shares issued		43,700,000	35,276,250		46,000,000		10,000,000	4,400,000	79,000,000.0
Common Stock Forward
Capped Call and Common Stock Forward
Common stock shares issued									14,397,906
3.75% Convertible Senior Notes
Capped Call and Common Stock Forward
Interest rate (as a percent)	3.75%			3.75%				3.75%	3.75%		3.75%
Principal amount	$ 200,000			$ 212,463				$ 212,463	$ 212,463		$ 12,500
Share Price								$ 33.91	$ 33.91
Convertible senior notes								$ 1,300,000	$ 1,300,000
Percentage of principal amount to be redeemed	100.00%
3.75% Convertible Senior Notes | Capped Call
Capped Call and Common Stock Forward
Capped call options amount	$ 16,200
Cap price	$ 6.7560
Premium (as a percent)	60.00%
Share Price	$ 4.11
7.5% Convertible Senior Note
Capped Call and Common Stock Forward
Interest rate (as a percent)						7.50%		7.50%	7.50%	7.50%
Principal amount						$ 40,000
Percentage of principal amount to be redeemed						120.00%
7.5% Convertible Senior Note | Common Stock Forward
Capped Call and Common Stock Forward
Net cost incurred									$ 27,500
5.5% Convertible Senior Notes
Capped Call and Common Stock Forward
Interest rate (as a percent)	5.50%			5.50%				5.50%	5.50%			5.50%
Principal amount	$ 100,000				$ 100,000			$ 160	$ 160			$ 100,000
5.5% Convertible Senior Notes | Capped Call
Capped Call and Common Stock Forward
Capped call options amount				$ 16,000
Cap price				$ 3.82
Premium (as a percent)				100.00%
Share Price				$ 1.91
Recorded in additional paid-in capital				$ 24,200
Percentage of principal amount to be redeemed				100.00%