Financial Instruments - Warrants (Details) $ / shares in Units, $ in Thousands, shares in Millions		3 Months Ended	12 Months Ended
	May 01, 2017 day $ / shares shares	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jan. 01, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Class of Warrant or Right [Line Items]
Equity reclassification		$ 68,667	$ 31,067		$ 27,540	$ 12,130
Fair value adjustment		7,600
Reclassification Adjustment
Class of Warrant or Right [Line Items]
Equity reclassification			10,290
Derivative and warrant liabilities				$ 10,300
Non-Public Warrants July 2019
Class of Warrant or Right [Line Items]
Fair value adjustment		(1,400)
Non-Public Warrants December 2019
Class of Warrant or Right [Line Items]
Fair value adjustment			(6,100)
Non-Public Warrants December 2020
Class of Warrant or Right [Line Items]
Fair value adjustment			4,700
Additional Paid-in Capital
Class of Warrant or Right [Line Items]
Equity reclassification		$ (425,224)	(434,917)		$ (433,136)	$ (432,577)
Additional Paid-in Capital | Reclassification Adjustment
Class of Warrant or Right [Line Items]
Equity reclassification			$ 10,290	$ 10,300
Common Stock
Class of Warrant or Right [Line Items]
Number of securities called by issued warrants (in shares) | shares	20.9
Share price of warrants (in dollars per share) | $ / shares	$ 11.50
Common Stock | Private Placement
Class of Warrant or Right [Line Items]
Number of securities called by issued warrants (in shares) | shares	7.5
Common Stock | Public Investors
Class of Warrant or Right [Line Items]
Number of securities called by issued warrants (in shares) | shares	13.4
Share price of warrants (in dollars per share) | $ / shares	$ 0.01
Share price required for redemption (in usd per share) | $ / shares	$ 18.00
Trading days threshold for redemption | day	20
Trading day period for redemption | day	30