Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Accounting Policies [Abstract]
Net loss	$ 8,427	$ 9,688	$ 50,712	$ 34,618	$ 18,115	$ 85,330
Fair value adjustment to warrants - Notes 11 and 18	651		(922)		10,144	(922)
Net cash used in operating activities					21,317	57,642
Cash	30,220		47,293		30,220	47,293	$ 56,363
Working capital	63,600				63,600
Liabilities	219,617		208,512		219,617	208,512	216,009
Accumulated deficit	538,874		$ 469,697		538,874	$ 469,697	$ 520,759
Debt, amount due in next 12 months	$ 9,600				$ 9,600