Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (32,211)	$ (25,956)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	848	745
Stock-based compensation	6,402	3,865
Amortization of premiums and discounts on marketable securities	579	1,045
Amortization of debt discount and issuance costs and other non-cash interest	106	0
Loss on disposition of fixed assets	4	0
Changes in operating assets and liabilities
Prepaid expenses, other current assets and other long-term assets	(1,191)	(21)
Accounts payable, accrued and other current liabilities	(560)	(576)
Operating lease liabilities	(580)	(504)
Net cash used in operating activities	(26,603)	(21,402)
Cash flows from investing activities:
Purchases of property and equipment	(632)	(24)
Purchases of marketable securities	(142,080)	(37,913)
Maturities of marketable securities	84,689	53,500
Net cash (used in) provided by investing activities	(58,023)	15,563
Cash flows from financing activities:
Proceeds from issuance of common stock and warrants, net of issuance costs	126,542	10,673
Proceeds from issuance of common stock under employee stock incentive plans	628	344
Net cash provided by financing activities	127,170	11,017
Effect of exchange rate changes on cash and cash equivalents	(39)	(24)
Net increase (decrease) in cash and cash equivalents	42,505	5,154
Cash and cash equivalents at the beginning of period	62,882	21,228
Cash and cash equivalents at the end of period	105,387	26,382
Supplemental disclosures of noncash investing and financing information:
Reclassification of employee stock liability to equity upon vesting	0	14
Unpaid offering costs in accrued liabilities	0	25
Purchase of property and equipment in accounts payable	557	16
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	$ 219	$ 0