Income Taxes - Net Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Tangible and intangible depreciable assets	$ 32,180	$ 6,978
Stock compensation	19,183	12,321
Provisions	2,510	934
Other, net	0	35
Lease liability	8,800	137
Net operating loss carry forwards	182,536	116,345
Capital loss carryforward	114	178
Canada scientific research and experimental development expenditures	5,471	5,471
U.S. research and development tax credits	28,834	17,080
Total gross deferred tax assets	279,628	159,479
Less valuation allowance	(270,368)	(159,357)
Net deferred tax assets	9,260	122
Deferred tax liabilities:
Right-of-use asset	(8,377)	(122)
Non-current investment	(883)	0
Net deferred income taxes	$ 0	$ 0