Convertible Senior Notes - Narrative (Details) $ / shares in Units, shares in Millions	1 Months Ended			3 Months Ended			6 Months Ended	12 Months Ended
	Nov. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) day	Feb. 28, 2018 USD ($) shares	Mar. 31, 2021 USD ($) day $ / shares shares	Mar. 31, 2020 day	Dec. 31, 2018 day	Jun. 30, 2020 day	Dec. 31, 2020 USD ($) day
Debt Instrument [Line Items]
Total cost of bond hedge			$ 41,700,000
Number of warrants issued, subject to anti-dilution adjustments (in shares) | shares			4.0
Warrant strike price (usd per share) | $ / shares				$ 78.75
Proceeds from bond hedge			$ 22,400,000
Convertible Senior Notes Due February 2023
Debt Instrument [Line Items]
Remaining amortization period for debt discount and debt issuance costs				1 year 10 months 24 days
Convertible Senior Notes Due February 2023 | Convertible Debt
Debt Instrument [Line Items]
Interest rate			0.75%
Principal amount			$ 230,000,000.0
Initial conversion rate of common stock			0.0174292
Conversion price (usd per share) | $ / shares				$ 57.38
Principal amount exchanged	$ 181,900,000
Carrying value	42,900,000			$ 43,126,000				$ 42,619,000
Loss on extinguishment of debt	8,900,000
Unamortized debt issuance costs	$ 2,000,000.0			$ 446,000				$ 501,000
Limitation on sale of common stock, sale price threshold, number of trading days | day				20		20	20	20
Limitation on sale of common stock, sale price threshold, trading period | day				30		30	30	30
Threshold percentage of stock price trigger				130.00%		130.00%	130.00%	130.00%
Number of consecutive business days			5 days
Percentage of closing sale price in excess of convertible notes			98.00%
Redemption price percentage			100.00%
If-converted value of convertible note that exceed principal amount				$ 35,900,000
Closing price of common stock (in dollars per share) | $ / shares				$ 100.20
Effective interest rate of liability component			5.875%
Issuance costs attributable to the liability component			$ 5,300,000
Net issuance costs related to the equity component			$ 1,500,000
Number of securities called by warrants (in shares) | shares	0.7		0.9
Number of warrants issued, subject to anti-dilution adjustments (in shares) | shares				0.2
Proceeds from bond hedge	$ 171,700,000
Convertible Senior Notes Due February 2023 | Convertible Debt | Warrant Transaction
Debt Instrument [Line Items]
Number of securities called by warrants (in shares) | shares	3.2
Payments for Repurchase of Warrants	$ 137,500,000
Convertible Senior Notes Due June 2026
Debt Instrument [Line Items]
Remaining amortization period for debt discount and debt issuance costs				5 years 2 months 12 days
Convertible Senior Notes Due June 2026 | Convertible Debt
Debt Instrument [Line Items]
Interest rate		0.75%
Principal amount		$ 316,300,000
Initial conversion rate of common stock				0.0112851
Conversion price (usd per share) | $ / shares				$ 88.61
Carrying value				$ 246,021,000				$ 243,159,000
Unamortized debt issuance costs				4,909,000				5,114,000
Limitation on sale of common stock, sale price threshold, number of trading days | day		20			20
Limitation on sale of common stock, sale price threshold, trading period | day		30			30
Threshold percentage of stock price trigger		130.00%			130.00%
Number of consecutive business days		5 days
Percentage of closing sale price in excess of convertible notes		98.00%
Redemption price percentage		100.00%
If-converted value of convertible note that exceed principal amount				$ 41,400,000
Closing price of common stock (in dollars per share) | $ / shares				$ 100.20
Effective interest rate of liability component		5.38%
Issuance costs attributable to the liability component		$ 6,400,000
Net issuance costs related to the equity component		2,900,000
Initial strike price (in usd per share) | $ / shares				88.6124
Initial cap price (in usd per share) | $ / shares				$ 139.00
Cost incurred in connection with capped calls		$ 40,800,000
Convertible Notes Due 2025
Debt Instrument [Line Items]
Remaining amortization period for debt discount and debt issuance costs				4 years 7 months 6 days
Convertible Notes Due 2025 | Convertible Debt
Debt Instrument [Line Items]
Interest rate	0.125%
Principal amount	$ 350,000,000.0
Initial conversion rate of common stock	0.0071355
Conversion price (usd per share) | $ / shares	$ 140.14			$ 140.14
Principal amount received in 2025 notes	$ 210,700,000
Shares issued from exchange on convertible senior notes (in shares) | shares	1.3
Carrying value				$ 275,361,000				271,690,000
Unamortized debt issuance costs				$ 4,956,000				$ 5,235,000
Limitation on sale of common stock, sale price threshold, number of trading days | day				20
Limitation on sale of common stock, sale price threshold, trading period | day				30
Threshold percentage of stock price trigger				130.00%
Number of consecutive business days				5 days
Percentage of closing sale price in excess of convertible notes				98.00%
Redemption price percentage	100.00%
Effective interest rate of liability component				5.00%
Issuance costs attributable to the liability component	$ 5,400,000
Net issuance costs related to the equity component	$ 1,500,000
Initial strike price (in usd per share) | $ / shares	$ 140.1443
Initial cap price (in usd per share) | $ / shares	$ 211.54
Cost incurred in connection with capped calls	$ 39,800,000
Principal amount, additional	$ 139,300,000