CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities
Net loss	$ (31,491)	$ (34,005)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	273	367
Accretion related to marketable securities	12	207
Stock-based compensation	2,072	3,494
Loss from equity method investment	5,367	2,272
Changes in operating assets and liabilities:
Accounts receivable - related party	4	(276)
Prepaid and other current assets	202	(1,075)
Operating lease right-of-use asset	723	(1,772)
Other assets	(12)	135
Accounts payable	2,662	(1,133)
Accrued and other liabilities	1,489	352
Operating lease liability	(777)	1,575
Net cash used in operating activities	(19,476)	(29,859)
Cash flows from investing activities
Purchases of marketable securities	(46,890)	(4,863)
Maturities of marketable securities	27,765	28,422
Purchases of property and equipment	(269)
Net cash provided by (used in) investing activities	(19,394)	23,559
Cash flows from financing activities
Proceeds from issuance of common stock, net (includes $4,850 in aggregate gross proceeds from related parties for the three months ended March 31, 2021)		31,989
Proceeds from issuance of common stock in connection with at-the-market offering, net		28,954
Proceeds from exercise of common stock options		1,197
Net cash provided by financing activities		62,140
Net increase (decrease) in cash and cash equivalents	(38,870)	55,840
Cash and cash equivalents at beginning of the period	63,458	16,455
Cash and cash equivalents at end of the period	$ 24,588	$ 72,295