Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (46,759)	$ (25,048)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	781	753
Purchase net premium on marketable securities	239	(405)
Net amortization of premium (accretion of discount) on marketable securities	(23)	341
Stock-based compensation	4,118	3,837
Non-cash operating lease expense	191	219
Other	(7)	4
Changes in operating assets and liabilities:
License and development receivables	336	0
Prepaid expenses and other assets	(2,419)	(2,876)
Accounts payable	(1,352)	(55)
Operating lease liabilities	(250)	(155)
Deferred revenue	(914)	7,804
Accrued and other liabilities	(877)	(1,867)
Net cash used in operating activities	(46,936)	(17,448)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(37)	(480)
Purchases of marketable securities	(27,750)	(93,579)
Proceeds from maturities and sales of marketable securities	54,296	56,000
Net cash provided by (used in) investing activities	26,509	(38,059)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of common stock and pre-funded warrants in registered direct offering, net of offering costs	42,979	0
Proceeds from employee stock plan purchases and stock option exercises	184	403
Principal payments on finance lease obligation	(347)	(233)
Net cash provided by financing activities	42,816	170
Effect of exchange rate on cash, cash equivalents, and restricted cash	(95)	11
NET DECREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	22,294	(55,326)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH
Beginning of period	16,980	91,937
End of period	39,274	36,611
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Leased assets obtained in exchange for lease obligations	0	872
Unpaid amounts related to purchase of property and equipment	$ 0	$ 23