CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss	$ (57,433)	$ (52,450)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,117	3,136
Amortization of premiums and discounts on marketable securities	2,594	1,957
Stock-based compensation	7,182	7,778
Changes in operating assets and liabilities:
Prepaid expenses and other assets	234	(4,365)
Accounts payable	(95)	(955)
Accrued liabilities	(506)	(395)
Deferred rent	(30)	1,499
Net cash used in operating activities	(44,937)	(43,795)
Cash flows from investing activities:
Maturities of marketable securities	78,029	171,037
Purchases of marketable securities	(13,267)	(121,900)
Purchases of property and equipment	(1,251)	(1,535)
Net cash provided by investing activities	63,511	47,602
Cash flows from financing activities:
Proceeds from exercise of stock options	66	85
Proceeds from shares issued under ESPP	73
Payments of the term loan		(3,473)
Net cash provided by (used in) financing activities	139	(3,388)
Net increase in cash, cash equivalents and restricted cash	18,713	419
Cash, cash equivalents and restricted cash - beginning of period	12,376	36,284
Cash, cash equivalents and restricted cash - end of period	31,089	36,703
Supplemental disclosures of cash flow information:
Cash paid for interest	$ 68	$ 139