CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (13,266)	$ (32,829)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	113	189
Non-cash lease cost	236	221
Share-based compensation	2,170	3,203
Unrealized foreign currency transaction (gain) loss	0	(11)
Accretion of discount on marketable securities	0	23
Change in fair value of derivative liability	0	193
Non-cash interest expense associated with the sale of future royalties	0	2,488
Changes in operating assets and liabilities:
Other receivables	(781)	661
Prepaid expenses and other current assets	(164)	31
Other assets	0	285
Accounts payable	(34)	3,679
Accrued expenses and other current liabilities	(111)	(5,290)
Deferred revenue, current and non-current	(740)	(246)
Other long-term liabilities	(11)	(10)
Operating lease liability	(265)	(240)
Net cash used in operating activities	(12,853)	(28,223)
Cash flows from investing activities:
Purchases of marketable securities	0	(26,970)
Proceeds from maturities of marketable securities	0	10,906
Net cash provided by (used in) investing activities	0	(16,064)
Cash flows from financing activities:
Proceeds from the issuance of common stock, net of issuance costs	0	3,626
Proceeds from stock option exercises	0	188
Net cash provided by financing activities	0	3,814
Net decrease in cash and cash equivalents:	(12,853)	(40,473)
Cash, cash equivalents and restricted cash at beginning of period	109,107	112,584
Cash, cash equivalents and restricted cash at end of period	$ 96,254	$ 72,111