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	$ (25,140)	$ (25,101)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,062	1,131
Accretion of (discount) premium on investments	(144)	36
Stock-based compensation	2,647	3,130
Non-cash interest expense related to sale of future royalties	178	340
Non-cash revenue related to sale of future royalties	(20)	(71)
Change in operating assets and liabilities:
Accounts receivable	(244)	(10)
Prepaid expenses and other assets	1,067	(4,498)
Accounts payable	(270)	113
Deferred grant revenue	(397)	0
Other accrued liabilities	(4,199)	(183)
Net cash used in operating activities	(24,460)	(25,113)
Cash flows from investing activities:
Purchases of property and equipment	(1,239)	(1,346)
Purchases of investments	0	(8,522)
Proceeds from maturities of investments	26,700	13,600
Net cash provided by investing activities	25,461	3,732
Cash flows from financing activities:
Net proceeds from issuance of common stock through ATM facilities	1,430	992
Shares acquired to settle employee tax withholding liabilities	(10)	0
Proceeds from issuance of common stock upon exercise of stock options	0	48
Net cash provided by financing activities	1,420	1,040
Net increase (decrease) in cash, cash equivalents and restricted cash	2,421	(20,341)
Cash, cash equivalents and restricted cash at beginning of the period	46,013	143,745
Cash, cash equivalents and restricted cash at end of the period	48,434	123,404
Supplemental disclosure of non-cash investing and financing activity:
Operating lease liabilities arising from obtaining right-of-use assets	296	125
Acquisition of property and equipment included in accounts payable and accrued expenses	$ 246	$ 505