Warrant Transaction Agreements - Amazon.com, Inc. Transaction Agreement (Details) $ / shares in Units, $ in Thousands						3 Months Ended		12 Months Ended
	Jun. 11, 2021 shares	Dec. 31, 2020 USD ($) $ / shares shares	Nov. 02, 2020 USD ($) installment $ / shares shares	Jan. 01, 2019 USD ($) installment shares	Apr. 04, 2017 USD ($) shares	Mar. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Apr. 30, 2017 shares
Class of Warrant or Right [Line Items]
Selling, general and administrative						$ 25,579	$ 11,109
Risk-free interest rate		0.58%	0.58%					0.58%
Volatility		75.00%	75.00%					75.00%
Expected average term			6 years 5 months 1 day					6 years 3 months 3 days
Exercise price | $ / shares		$ 13.81	$ 13.81					$ 13.81
Stock price | $ / shares		$ 33.91	15.47					$ 33.91
Warrant shares exercised (in shares) | shares						16,489,014
Warrant Transaction Agreements
Class of Warrant or Right [Line Items]
Shares of common stock that can be purchased from warrants issued (in shares) | shares					55,286,696						55,286,696
Reduction in revenue						$ 104	$ 1,300
Warrant shares vested (in shares) | shares		55,286,696						55,286,696
Fair value of warrants per share | $ / shares		$ 26.95	$ 10.57					$ 26.95
Warrant shares exercised (in shares) | shares	4,534,130					9,214,449
Tranche one of warrants issued with the Amazon.com, Inc transaction agreement
Class of Warrant or Right [Line Items]
Shares of common stock that can be purchased from warrants issued (in shares) | shares					5,819,652
Cash payments to be received under agreement					$ 600,000
Selling, general and administrative					$ 6,700
Exercise price calculation						$1.1893
Tranche two of warrants issued with the Amazon.com, Inc. Transaction Agreement
Class of Warrant or Right [Line Items]
Cash payments to be received under agreement				$ 50,000
Reduction in revenue								$ 9,000	$ 4,100	$ 9,800
Warrant shares vested (in shares) | shares				29,098,260
Number of installments | installment				4
Tranche two of warrants issued with the Amazon.com, Inc. Transaction Agreement | Maximum
Class of Warrant or Right [Line Items]
Cash payments to be received under agreement				$ 200,000
Tranche three of warrants issued with the Amazon.com, Inc. Transaction Agreement
Class of Warrant or Right [Line Items]
Cash payments to be received under agreement			$ 50,000
Reduction in revenue		$ 399,700						24,100
Warrant shares vested (in shares) | shares			20,368,784
Number of installments | installment			8
Exercise price of warrants (in dollars per share) | $ / shares						$ 13.81
Fair value of warrants per share | $ / shares			$ 10.57
Warrant percentage weighted average share price						90.00%
Tranche three of warrants issued with the Amazon.com, Inc. Transaction Agreement | Maximum
Class of Warrant or Right [Line Items]
Cash payments to be received under agreement			$ 400,000
Warrant Issued With Amazon
Class of Warrant or Right [Line Items]
Reduction in revenue								$ 399,700
Warrant shares vested (in shares) | shares		5,354,905	12,730,490					5,354,905
Provision for loss contracts related to services								$ 12,800