Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (65,090,000)	$ (83,840,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	6,293,000	3,915,000
Loss on disposal of equipment	55,000	0
Amortization of discount on investments, net	(510,000)	(13,000)
Stock-based compensation	10,417,000	10,194,000
Non-cash interest expense related to sale of future royalties	573,000	988,000
Non-cash revenue related to sale of future royalties	(314,000)	(152,000)
Change in operating assets and liabilities:
Accounts receivable	(404,000)	71,000
Prepaid expenses and other assets	2,760,000	(4,037,000)
Accounts payable	(2,699,000)	2,528,000
Deferred grant revenue	(1,921,000)	0
Other accrued liabilities	(6,092,000)	4,719,000
Net cash used in operating activities	(56,932,000)	(65,627,000)
Cash flows from investing activities:
Purchases of property and equipment	(1,975,000)	(5,700,000)
Proceeds from sale of property and equipment	120,000	0
Cash paid for right-of-use assets	0	(5,038,000)
Purchases of investments	(27,497,000)	(48,178,000)
Proceeds from maturities of investments	58,200,000	22,700,000
Net cash provided by (used in) investing activities	28,848,000	(36,216,000)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of warrants	0	2,000
Shares acquired to settle employee tax withholding liabilities	(39,000)	0
Proceeds from issuance of common stock upon exercise of stock options	17,000	214,000
Proceeds from issuance of common stock under the employee stock purchase plan	298,000	0
Net cash provided by financing activities	15,309,000	8,866,000
Net decrease in cash, cash equivalents and restricted cash	(12,775,000)	(92,977,000)
Cash, cash equivalents and restricted cash at beginning of the period	46,013,000	143,745,000
Cash, cash equivalents and restricted cash at end of the period	33,238,000	50,768,000
Supplemental disclosure of non-cash investing and financing activity:
Operating lease liabilities arising from obtaining right-of-use assets	296,000	9,997,000
Acquisition of property and equipment included in accounts payable and accrued expenses	14,000	1,738,000
Registered Direct Offering [Member]
Cash flows from financing activities:
Net proceeds from issuance of common stock	13,603,000	0
At-the-market Facility [Member]
Cash flows from financing activities:
Net proceeds from issuance of common stock	$ 1,430,000	$ 8,650,000