CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net loss		$ (17,211)	$ (9,144)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	$ 26	51	38
Stock-based compensation expense		249	81
Accretion on marketable securities		(81)	(22)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		(465)	(337)
Accounts payable		454	(393)
Accrued expenses		2,105	(396)
Net cash used in operating activities		(14,898)	(10,173)
Investing activities
Purchases of marketable securities		(18,908)	(12,771)
Maturities of marketable securities		21,520	9,225
Purchases of property and equipment		(168)	(43)
Net cash provided by (used in) investing activities		2,444	(3,589)
Financing activities
Proceeds from issuance of Series A-2 Convertible Preferred Stock, net of issuance costs		33,638	22,898
Payment of initial public offering costs		(1,855)
Proceeds from exercise of stock options		154	34
Net cash provided by financing activities		31,937	22,932
Net increase in cash, cash equivalents and restricted cash		19,483	9,170
Cash, cash equivalents and restricted cash at beginning of period		31,735	35,966
Cash, cash equivalents and restricted cash at end of period	51,218	51,218	45,136
Supplemental cash flow information:
Cash and cash equivalents	50,863	50,863	45,136
Restricted cash	355	355
Cash, cash equivalents and restricted cash at end of period	$ 51,218	51,218	$ 45,136
Property and equipment unpaid at end of period		431
Deferred offering costs unpaid at end of period		738
Deferred lease incentive - non-cash		$ 238