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	$ (19,014)	$ (34,542)
Adjustments to reconcile net loss to net cash provided by (used in)    operating activities:
Depreciation and amortization expense	691	802
Stock-based compensation expense	3,938	4,659
Non-cash interest expense related to note payable	296	816
Net amortization of premiums and discounts on marketable securities	276	357
Non-cash operating lease cost	1,172	1,007
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,660)	(1,125)
Other assets	157	74
Accounts payable	(1,128)	(487)
Accrued expenses and other current liabilities	(2,395)	(1,704)
Operating lease liability	(1,304)	(1,086)
Net cash used in operating activities	(18,971)	(31,229)
Cash flows from investing activities:
Purchases of property and equipment	(146)	0
Purchases of marketable securities	(15,690)	(81,311)
Proceeds from sales or maturities of marketable securities	30,745	0
Net cash provided by (used in) investing activities	14,909	(81,311)
Cash flows from financing activities:
Proceeds from issuance of common stock upon public offering, net	22,666	18,982
Proceeds from employee stock purchases	164	118
Proceeds from exercise of stock options	11	1,634
Net cash provided by financing activities	22,841	20,734
Net increase (decrease) in cash and cash equivalents and restricted cash	18,779	(91,806)
Cash and cash equivalents and restricted cash at beginning of period	57,640	176,736
Cash and cash equivalents and restricted cash at end of period	76,419	84,930
Supplemental disclosure of cash flow information:
Cash paid for interest	1,097	636
Supplemental disclosure of non-cash investing and financing activities:
Additional right-of-use asset and related lease liability	755	0
Purchases of property and equipment included in accounts payable and accrued expenses	92	0
Conversion of note payable into shares of common stock	$ 0	$ 1,500