Income Tax - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Depreciation of property and equipment, net	$ 98	$ 108	$ 84
Research and experimental capitalization	22,476	0	0
Share-based compensation	1,787	0	0
Accrued expenses	1,800	0	0
Government grants	189	496	400
Deferred revenue	3,378	3,733	2,069
Qualified donation	12,947	10,246	7,627
Net operating loss carry forwards	241,397	175,101	94,954
Less: valuation allowance	(284,072)	(189,684)	(105,134)
Deferred tax assets, net	$ 0	$ 0	$ 0