Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities
Net (loss) income	$ (49,851,000)	$ 75,208,000
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Depreciation and amortization	447,000	375,000
Stock-based compensation	12,771,000	9,953,000
Non-cash: Net accretion of available-for-sale debt securities	(5,386,000)	0
Change in operating lease right-of-use assets	0	4,000
Changes in operating assets and liabilities:
Grants receivable	584,000	(333,000)
Research and development tax credits receivable	(729,000)	(41,000)
Refundable income taxes	(1,839,000)	7,544,000
Prepaid expenses and other current assets	702,000	4,360,000
Accounts payable	(2,512,000)	6,447,000
Accrued expenses and other liabilities	989,000	(2,286,000)
Income tax payable	0	12,965,000
Deferred income	1,318,000	189,000
Deferred revenue	(12,595,000)	(194,238,000)
Unrecognized tax benefits	0	25,529,000
Net cash used in operating activities	(56,101,000)	(54,324,000)
Cash flows from investing activities
Purchases of investments	(139,037,000)	0
Proceeds from maturities of investments	128,265,000	0
Purchase of property and equipment	(819,000)	(738,000)
Purchase of other assets	0	(99,000)
Net cash used in investing activities	(11,591,000)	(837,000)
Cash flows from financing activities
Proceeds from issuance of common stock upon exercise of options	796,000	611,000
Net cash provided by financing activities	796,000	611,000
Effects of exchange rate changes on cash, cash equivalents and restricted cash	(1,659,000)	(2,134,000)
Net decrease in cash, cash equivalents and restricted cash	(68,555,000)	(56,684,000)
Cash, cash equivalents and restricted cash at beginning of period	285,038,000	848,835,000
Cash, cash equivalents and restricted cash at end of period	216,483,000	792,151,000
Non-cash investing and financing activities
Capital expenditure included in accounts payable	20,000	(57,000)
Operating lease liabilities arising from obtaining right-of-use assets	1,059,000	177,000
Unrealized gain on available-for-sale securities	(1,620,000)	0
Supplemental disclosure of cash flows
Cash paid for taxes	$ 4,321,000	$ 6,740,000