Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (18,325)	$ (18,803)
Adjustments to reconcile net loss to net cash used in operating activities:
Compensation expense related to vesting of common stock issued to Xontogeny	0	39
Depreciation	141	102
Accrued interest on marketable securities	305	0
Stock-based compensation expense	1,690	0
Net realized gain (loss) on sale of marketable securities	(121)	41
Amortization of premium on marketable securities	1,210	83
Gain (loss) from foreign exchange	3	39
Changes in operating assets and liabilities:
Incentive and tax receivables	151	(112)
Prepaid expenses and other assets	(350)	(90)
Accounts payable	1,505	4,179
Other liabilities	(1,213)	29
Net cash used in operating activities	(15,004)	(14,571)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(477)	(91)
Purchases of available-for-sale marketable securities	(165,914)	(14,423)
Proceeds from sales and maturities of available-for-sale marketable securities	105,889	21,715
Net cash (used in) provided by investing activities	(60,502)	7,201
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from initial public offering	90,506
Proceeds from exercise of stock options	477	0
Net cash provided by financing activities	90,983
Net change in cash and cash equivalents	15,477	(7,370)
Cash and cash equivalents at beginning of period	2,416	9,808
Effect of exchange rates on cash	0	39
Cash and cash equivalents at end of period	17,893	2,477
Supplemental non-cash disclosure: NONCASH INVESTING AND FINANCING ACTIVITY:
Deferred offering costs included in accounts payable and accrued liabilities	0	725
Reclassification of par to additional paid-in-capital	2	0
Reclassification of series A and B convertible preferred stock to common stock	72,925	0
Unrealized gain on available-for-sale marketable securities	$ 121