Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net loss	$ (26,488)	$ (21,536)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	217	187
Stock-based compensation	3,151	1,442
Non-cash interest expense	210	23
Accretion of discounts on investments, net	(91)	(579)
Amortization of right-of-use asset	463	432
Change in fair value of warrant liability	75
Changes in operating assets and liabilities
Prepaid expenses and other current assets	29	89
Accounts payable and accrued liabilities	(1,260)	1,646
Lease liability	(427)	(374)
Net cash used in operating activities	(24,121)	(18,670)
Investing activities:
Purchases of property and equipment	(172)	(56)
Purchases of short-term investments	(7,944)	(48,827)
Sale and maturities of short-term investments	37,033	60,225
Net cash provided by investing activities	28,917	11,342
Financing activities:
Proceeds from issuance of common stock from initial public offering, net of issuance costs	77,750
Proceeds from exercise of common stock options	69	30
Repurchase of unvested common stock	(2)	(1)
Proceeds from issuance of long-term debt, net of issuance cost		9,717
Net cash provided by financing activities	77,817	9,746
Net increase in cash and cash equivalents	82,613	2,418
Cash and cash equivalents at beginning of period	15,668	15,965
Cash and cash equivalents at end of period	98,281	18,383
Supplemental disclosure of cash flow information:
Cash paid for interest	554
Supplemental non-cash investing and financing activities:
Conversion of convertible preferred stock to common stock	122,465
Conversion of convertible preferred stock warrant to common stock warrant	259
Issuance costs in accounts payable and accrued liabilities	852
Initial fair value of warrant liability		184
Vesting of common stock	$ 73	$ 75