Convertible Notes (Details)					1 Months Ended	3 Months Ended		6 Months Ended
	Nov. 03, 2021 shares	Oct. 22, 2021 USD ($) $ / shares	Jan. 01, 2021 USD ($)	Nov. 16, 2020 USD ($) $ / shares shares	Nov. 30, 2020 USD ($) day $ / shares	Jun. 30, 2022 USD ($) $ / shares	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) $ / shares	Dec. 02, 2021 $ / shares
Debt Instrument [Line Items]
Purchase of capped call options associated with convertible notes				$ 46,000,000	$ 46,000,000
Prepayment of forward stock repurchase transaction				$ 55,000,000	55,000,000
Common stock, par value (in dollars per share) | $ / shares						$ 0.001		$ 0.001		$ 0.001
Additional Paid in Capital						$ (992,964,000)		$ (992,964,000)		$ (964,401,000)
Accumulated Deficit						$ 1,229,432,000		$ 1,229,432,000		$ 1,106,377,000
Exercise price (in dollars per share) | $ / shares						$ 9.00		$ 9.00		$ 9.00	$ 9.00
Underlying common stock (in shares) | shares				1,994,198
Shares delivered to the company (in shares) | shares								71,174
Cumulative Effect, Period of Adoption, Adjustment
Debt Instrument [Line Items]
Additional Paid in Capital			$ 93,500,000
Accumulated Deficit			1,500,000
Capped Call | Common stock
Debt Instrument [Line Items]
Exercise price (in dollars per share) | $ / shares				$ 55.16
Class of warrant or right, premium percentage				100.00%
Convertible Senior Notes Due 2025 | Convertible Debt
Debt Instrument [Line Items]
Debt instrument, face amount					$ 280,000,000
Debt instrument, stated interest rate					4.00%
Proceeds from debt, net of issuance costs			$ 271,100,000		$ 271,100,000
Debt instrument, convertible, conversion ratio					30.2151
Debt instrument, convertible, conversion price (in dollars per share) | $ / shares					$ 33.096
Debt instrument, redemption price, percentage					100.00%
Debt issuance costs					$ 8,900,000
Debt instrument, term					5 years
Long-term debt					$ 177,600,000	$ 259,100,000		$ 259,100,000
Debt instrument, convertible, carrying amount of equity component					$ 93,500,000
Exchange Agreement, amount of principal amount converted into common stock		$ 15,000,000
Exchange Agreement, weighted average price per share floor (in dollars per share) | $ / shares		$ 5.62
Exchange Agreement, threshold trading days		5 days
Common stock being exchanged (in shares) | shares	1,094,848
Principal amount of convertible notes						265,000,000		265,000,000
Unamortized debt discount and issuance costs						5,900,000		5,900,000
Debt interest expense						3,100,000	$ 3,200,000	6,100,000	$ 6,400,000
Debt fair value						$ 147,700,000		$ 147,700,000		$ 140,300,000
Convertible Senior Notes Due 2025 | Convertible Debt | Period One
Debt Instrument [Line Items]
Common stock, par value (in dollars per share) | $ / shares					$ 0.001
Debt instrument, convertible, threshold percentage of stock price trigger					130.00%
Debt instrument, convertible, threshold trading days | day					20
Average trading-day period | day					30
Number of business days | day					5
Number of consecutive trading days | day					5
Debt instrument, convertible, threshold percentage of last reported sale price					98.00%
Convertible Senior Notes Due 2025 | Convertible Debt | Period Two
Debt Instrument [Line Items]
Debt instrument, convertible, threshold percentage of stock price trigger					130.00%
Debt instrument, convertible, threshold trading days | day					20
Average trading-day period | day					30
Debt instrument, redemption price, percentage					100.00%
Debt instrument, required amount outstanding					$ 125,000,000
Convertible Senior Notes Due 2025 | Convertible Debt | Long-term Debt
Debt Instrument [Line Items]
Debt issuance costs					5,800,000
Convertible Senior Notes Due 2025 | Convertible Debt | Additional Paid-In Capital
Debt Instrument [Line Items]
Debt issuance costs					$ 3,100,000