CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (UNAUDITED) - USD ($) $ in Thousands		Total	Conversion from Class B common stock	Private Placement	Sprott Credit Agreement	2.0 Lien Notes to common stock	1.5 Lien Notes into common stock	1.25 Lien Notes into common stock	Common Stock		Common Stock Conversion from Class B common stock	Common Stock Private Placement		Common Stock Sprott Credit Agreement	Common Stock 2.0 Lien Notes to common stock		Common Stock 1.5 Lien Notes into common stock		Common Stock 1.25 Lien Notes into common stock	Treasury Stock		Treasury Stock 2.0 Lien Notes to common stock	Additional Paid-in Capital		Additional Paid-in Capital Conversion from Class B common stock	[1]	Additional Paid-in Capital Private Placement	[1]	Additional Paid-in Capital Sprott Credit Agreement	[1]	Additional Paid-in Capital 2.0 Lien Notes to common stock	[1]	Additional Paid-in Capital 1.5 Lien Notes into common stock	[1]	Additional Paid-in Capital 1.25 Lien Notes into common stock	[1]	Accumulated Deficit	Accumulated Deficit 2.0 Lien Notes to common stock	Accumulated Deficit 1.5 Lien Notes into common stock
Beginning balance (in shares) at Dec. 31, 2019	[1]								345,431											22,103
Beginning balance at Dec. 31, 2019		$ (439,251)							$ 0	[1]										$ 0	[1]		$ 5,187	[1]													$ (444,438)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		(34,618)																																			(34,618)
Ending balance (in shares) at Mar. 31, 2020	[1]								345,431											22,103
Ending balance at Mar. 31, 2020		(473,869)							$ 0	[1]										$ 0	[1]		5,187	[1]													(479,056)
Beginning balance (in shares) at Dec. 31, 2019	[1]								345,431											22,103
Beginning balance at Dec. 31, 2019		(439,251)							$ 0	[1]										$ 0	[1]		5,187	[1]													(444,438)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		(85,330)
Ending balance (in shares) at Jun. 30, 2020	[1]								50,160,042											0
Ending balance at Jun. 30, 2020		(15,831)							$ 5	[1]										$ 0	[1]		453,861	[1]													(469,697)
Beginning balance (in shares) at Mar. 31, 2020	[1]								345,431											22,103
Beginning balance at Mar. 31, 2020		(473,869)							$ 0	[1]										$ 0	[1]		5,187	[1]													(479,056)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares issued upon conversion (in shares)	[1]										4,813,180				14,795,153		16,025,316		4,845,920			(22,103)
Common shares issued upon conversion			$ 12,814			$ 220,859	$ 145,685	$ 48,459							$ 2	[1]	$ 2	[1]							$ 12,814						$ 146,217		$ 160,252		$ 48,459			$ 74,640	$ (14,569)
Common shares issued (in shares)	[1]											7,596,309		496,634
Common shares issued				$ 75,963	$ 6,282							$ 1	[1]														$ 75,962		$ 6,282
Unredeemed SPAC shares of MUDS public stockholders (in shares)	[1]								1,197,704
Unredeemed SPAC shares of MUDS public stockholders		3,723																					3,723	[1]
Common shares issued to underwriter (in shares)	[1]								44,395
Common shares issued to underwriter		444																					444	[1]
Vesting of restricted stock units		1,802																					1,802	[1]
Equity issuance costs		(7,281)																					(7,281)	[1]
Net loss		(50,712)																																			(50,712)
Ending balance (in shares) at Jun. 30, 2020	[1]								50,160,042											0
Ending balance at Jun. 30, 2020		(15,831)							$ 5	[1]										$ 0	[1]		453,861	[1]													(469,697)
Beginning balance (in shares) at Dec. 31, 2020									59,901,306											0
Beginning balance at Dec. 31, 2020		16,617							$ 6											$ 0			537,370														(520,759)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation costs		507																					507
Vesting of restricted stock units		104																					104
Net loss		(9,688)																																			(9,688)
Ending balance (in shares) at Mar. 31, 2021									59,901,306											0
Ending balance at Mar. 31, 2021		7,540							$ 6											$ 0			537,981														(530,447)
Beginning balance (in shares) at Dec. 31, 2020									59,901,306											0
Beginning balance at Dec. 31, 2020		16,617							$ 6											$ 0			537,370														(520,759)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		(18,115)
Ending balance (in shares) at Jun. 30, 2021									59,964,980											0
Ending balance at Jun. 30, 2021		408							$ 6											$ 0			539,276														(538,874)
Beginning balance (in shares) at Mar. 31, 2021									59,901,306											0
Beginning balance at Mar. 31, 2021		7,540							$ 6											$ 0			537,981														(530,447)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation costs		1,011																					1,011
Vesting of restricted stock units (in shares)									63,674
Vesting of restricted stock units		0																					0
5-Year Private Warrants transferred to 5-Year Public Warrants		284																					284
Net loss		(8,427)																																			(8,427)
Ending balance (in shares) at Jun. 30, 2021									59,964,980											0
Ending balance at Jun. 30, 2021		$ 408							$ 6											$ 0			$ 539,276														$ (538,874)

[1] Retroactively restated January 1, 2020 and March 31, 2020 for the reverse recapitalization as described in Note 2 - Summary of Significant Accounting Policies, and the restated reclassification of the Company's 5-Year Private Warrants as described in Note 11 - Warrants.