CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (46,415)	$ (89,756)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	869	646
Non-cash lease cost	678	471
Impairment of assets	635	0
Share-based compensation	9,123	9,430
Unrealized foreign currency transaction loss	10	13
Accretion of premium (discount) on marketable securities	13	251
Change in fair value of derivative liabilities	(917)	(204)
Non-cash interest expense associated with the sale of future royalties	2,605	1,940
Loss on extinguishment of liability related to the sale of future royalties	3,581	0
Changes in operating assets and liabilities:
Other receivables	1,196	3,050
Prepaid expenses and other current assets	5,242	(2,808)
Tax incentive receivables	351	782
Other assets	(3)	(319)
Accounts payable	(484)	(53)
Accrued expenses and other current liabilities	(5,377)	2,109
Deferred revenue, current and non-current	21,892	10,643
Other long-term liabilities	(42)	(39)
Operating lease liabilities	(688)	(503)
Net cash used in operating activities	(7,731)	(64,347)
Cash flows from investing activities:
Purchases of marketable securities	(26,970)	(43,915)
Proceeds from maturities of marketable securities	60,777	51,548
other	0	39
Net cash provided by investing activities	33,807	7,672
Cash flows from financing activities:
Repayment of liability related to the sale of future royalties	(54,485)	0
Proceeds from sale of future royalties, net	0	49,750
Transaction costs from sale of future royalties	0	(2,210)
Royalty payments	0	(60)
Payment of offering costs	0	(248)
Proceeds from stock option exercises	420	1,450
Net cash provided by financing activities	(29,553)	84,050
Net increase (decrease) in cash and cash equivalents	(3,477)	27,375
Cash and cash equivalents at beginning of period	112,584	85,209
Cash and cash equivalents at end of period	109,107	112,584
Proceeds from the issuance of common stock, net of commissions
Cash flows from financing activities:
Proceeds from the issuance of common stock, net of issuance costs	14,234	7,831
Proceeds from the issuance of common stock related to the GSK Share Purchase Agreement
Cash flows from financing activities:
Proceeds from the issuance of common stock, net of issuance costs	10,278	0
Pfizer Purchase Agreement [Member]
Cash flows from financing activities:
Proceeds from the issuance of common stock, net of issuance costs	$ 0	$ 27,537