Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (20,672)	$ (2,709)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	1,639	1,090
Depreciation and amortization	47	46
Accretion on marketable securities	1,925	172
Changes in operating assets and liabilities:
Prepaid and other current assets	(1,199)	(174)
Other assets	252	387
Accounts payable, accrued liabilities and other liabilities	367	(2,068)
Net cash used in operating activities	(17,641)	(3,256)
Cash flows from investing activities:
Purchase of marketable securities	(137,329)	(21,819)
Sale of marketable securities	66,035	13,646
Purchase of property and equipment	(60)	(14)
Net cash used in investing activities	(71,354)	(8,187)
Cash flows from financing activities:
Proceeds from exercise of options	24	0
Tax withholding payments on net share settlement equity awards	(248)	(148)
Net proceeds from issuance of common stock	85,479	18,715
Net cash provided by financing activities	85,255	18,567
Net (decrease) increase in cash and cash equivalents	(3,740)	7,124
Cash and cash equivalents at beginning of period	16,512	14,032
Cash and cash equivalents at end of period	$ 12,772	$ 21,156