Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 848,537	$ 336,326
Grants receivable	4,022	133
Research and development tax credits receivable	524	192
Refundable income taxes	7,544	0
Prepaid expenses and other current assets	14,086	2,893
Total current assets	874,713	339,544
Property and equipment, net	2,072	1,352
Research and development tax credits receivable, net of current portion	2,004	3,286
Restricted cash	298	128
Right of use assets	5,329	0
Other assets	296	248
Total assets	884,712	344,558
Current liabilities:
Accounts payable	5,145	3,026
Accrued expenses and other current liabilities	17,157	7,486
Deferred income	827	4,486
Deferred revenue	280,225
Lease liabilities	770
Total current liabilities	304,124	14,998
Grants repayable	6,164	5,883
Lease liabilities, net of current portion	4,571
Unrecognized tax benefits	17,000	0
Other noncurrent liabilities	33	480
Total liabilities	331,892	21,361
Commitments and contingencies (Note 10)
Stockholders’ equity (deficit):
Preferred stock, $0.001 par value; 10,000,000 and zero shares authorized at December 31, 2021 and 2020, respectively, and zero shares issued or outstanding	0	0
Common stock, $0.001 par value, 150,000,000 shares authorized at December 31, 2021 and 2020, respectively; 35,466,001 and 35,044,758 shares issued and outstanding at December 31, 2021 and 2020, respectively	35	35
Additional paid-in capital	413,180	396,443
Accumulated other comprehensive (loss) income	(1,018)	617
Retained earnings (accumulated deficit)	140,623	(73,898)
Total stockholders' equity	552,820	323,197
Total liabilities and stockholders' equity	$ 884,712	$ 344,558