CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands		Total		Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjustment	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment	Previously Reported	Previously Reported Common Stock	Previously Reported Additional Paid-in Capital	Previously Reported Accumulated Deficit	Revision of Prior Period, Adjustment	Revision of Prior Period, Adjustment Common Stock	Revision of Prior Period, Adjustment Additional Paid-in Capital	Revision of Prior Period, Adjustment Accumulated Deficit
Balance at beginning of period (in shares) at Dec. 31, 2018		0								76,817,224				(76,817,224)
Balance at beginning of period at Dec. 31, 2018		$ 0								$ 278,062				$ (278,062)
Balance at end of period (in shares) at Sep. 30, 2019		0
Balance at end of period at Sep. 30, 2019		$ 0
Balance at beginning of period (in shares) at Dec. 31, 2018					260,406,343						60,166,667				200,239,676
Balance at beginning of period at Dec. 31, 2018		186,240		$ 0	$ 26	$ 284,779	$ 162	$ (98,565)	$ (162)	$ (91,822)	$ 1	$ 6,742	$ (98,565)	$ 278,062	$ 25	$ 278,037	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Series D redeemable convertible preferred stock, net of issuance costs (in shares)	[1]				6,671,998
Issuance of Series D redeemable convertible preferred stock, net of issuance costs	[1]	60,625			$ 1	60,624
Issuance of Series D redeemable convertible preferred stock for in-kind contribution (in shares)	[1]				5,132,291
Issuance of Series D redeemable convertible preferred stock for in-kind contribution	[1]	50,000				50,000
Exercise of stock options (in shares)					563
Exercise of stock options		0
Stock-based compensation		3,772				3,772
Net loss		(62,377)						(62,377)
Balance at end of period (in shares) at Sep. 30, 2019					272,211,195
Balance at end of period at Sep. 30, 2019		$ 238,260			$ 27	399,337		(161,104)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201807Member
Balance at beginning of period (in shares) at Jun. 30, 2019		0								76,817,224				(76,817,224)
Balance at beginning of period at Jun. 30, 2019		$ 0								$ 278,062				$ (278,062)
Balance at end of period (in shares) at Sep. 30, 2019		0
Balance at end of period at Sep. 30, 2019		$ 0
Balance at beginning of period (in shares) at Jun. 30, 2019					260,406,343						60,166,667				200,239,676
Balance at beginning of period at Jun. 30, 2019		141,964			$ 26	287,528		(145,590)		$ (136,098)	$ 1	9,491	(145,590)	$ 278,062	$ 25	278,037	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Series D redeemable convertible preferred stock, net of issuance costs (in shares)	[2]				6,671,998
Issuance of Series D redeemable convertible preferred stock, net of issuance costs	[2]	60,625			$ 1	60,624
Issuance of Series D redeemable convertible preferred stock for in-kind contribution (in shares)	[2]				5,132,291
Issuance of Series D redeemable convertible preferred stock for in-kind contribution	[2]	50,000	[1]			50,000
Exercise of stock options (in shares)					563
Exercise of stock options		0
Stock-based compensation		1,185				1,185
Net loss		(15,514)						(15,514)
Balance at end of period (in shares) at Sep. 30, 2019					272,211,195
Balance at end of period at Sep. 30, 2019		$ 238,260			$ 27	399,337		(161,104)
Balance at beginning of period (in shares) at Dec. 31, 2019		0								82,297,742				(82,297,742)
Balance at beginning of period at Dec. 31, 2019		$ 0								$ 383,987				$ (383,987)
Balance at end of period (in shares) at Sep. 30, 2020		0
Balance at end of period at Sep. 30, 2020		$ 0
Balance at beginning of period (in shares) at Dec. 31, 2019					270,826,092						60,167,334				210,658,758
Balance at beginning of period at Dec. 31, 2019		195,508			$ 27	383,961		(188,480)		(188,479)	$ 1	0	(188,480)	$ 383,987	$ 26	$ 383,961	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Series D redeemable convertible preferred stock, net of issuance costs (in shares)	[3]				6,581,340
Issuance of Series D redeemable convertible preferred stock, net of issuance costs	[3]	56,250			$ 1	56,249
Issuance of Series D redeemable convertible preferred stock for in-kind contribution (in shares)	[3]				9,443,353
Issuance of Series D redeemable convertible preferred stock for in-kind contribution	[3]	91,999			$ 1	91,998
Business Combination and PIPE financing (in shares)					72,272,942
Business Combination and PIPE financing		$ 616,220			$ 7	616,213
Exercise of stock options (in shares)		2,081,577			2,081,577
Exercise of stock options		$ 2,204				2,204
Common stock issued for warrants exercised (in shares)					22,877,806
Common stock issued for warrants exercised		263,064			$ 3	263,061
Stock-based compensation		91,736				91,736
Net loss		(237,275)						(237,275)
Balance at end of period (in shares) at Sep. 30, 2020					384,083,110
Balance at end of period at Sep. 30, 2020		$ 1,079,706			$ 39	1,505,422		(425,755)
Balance at end of period (in shares) at Sep. 30, 2020		0
Balance at end of period at Sep. 30, 2020		$ 0
Balance at beginning of period (in shares) at Jun. 30, 2020											360,910,639
Balance at beginning of period at Jun. 30, 2020										$ 881,595	$ 36	$ 1,189,845	$ (308,286)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)					294,665
Exercise of stock options		320				320
Common stock issued for warrants exercised (in shares)					22,877,806
Common stock issued for warrants exercised		263,064			$ 3	263,061
Stock-based compensation		52,196				52,196
Net loss		(117,469)						(117,469)
Balance at end of period (in shares) at Sep. 30, 2020					384,083,110
Balance at end of period at Sep. 30, 2020		$ 1,079,706			$ 39	$ 1,505,422		$ (425,755)

[1] Issuance of Series D redeemable convertible preferred stock has been retroactively restated to give effect to the recapitalization transaction.

[2] Issuance of Series D redeemable convertible preferred stock has been retroactively restated to give effect to the recapitalization transaction.

[3] Issuance of Series D redeemable convertible preferred stock has been retroactively restated to give effect to the recapitalization transaction.