Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net loss	$ (20,895,000)	$ (18,033,000)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	28,000	17,000
Stock-based compensation	2,984,000	1,660,000
Net unrealized (gain) loss on foreign currency transactions	(85,000)	19,000
Non-cash consulting expense	81,000
Amortization of term loan discount and issuance costs	195,000
Realized gain on investments	(13,000)	0
Amortization/accretion of investments, net	30,000	(327,000)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	862,000	495,000
Accounts payable	(229,000)	1,559,000
Accrued expenses	671,000	694,000
Net cash used in operating activities	(16,371,000)	(13,916,000)
Investing activities:
Purchases of property and equipment	(172,000)	(56,000)
Purchases of short-term investments	(30,314,000)	(36,095,000)
Maturities of short-term investments	28,930,000	39,315,000
Net cash (used in) provided by investing activities	(1,556,000)	3,164,000
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	35,758,000
Proceeds from issuance of notes payable, net of issuance costs		9,941,000
Proceeds from ESPP purchase	96,000
Net cash provided by financing activities	53,934,000	9,941,000
Effect of exchange rate changes on cash and cash equivalents	23,000	(40,000)
Net increase (decrease) in cash and cash equivalents	36,030,000	(851,000)
Cash and cash equivalents at beginning of period	13,219,000	28,508,000
Cash and cash equivalents at end of period	49,249,000	27,657,000
Supplemental disclosures of non-cash activities:
Equity issuance costs in accounts payable	50,000
Fair value of common stock warrants in connection with issuance of notes payable		266,000
Notes payable issuance costs in accounts payable		$ 58,000
ATM Facility
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	18,080,000
Lincoln Park Capital Fund, LLC
Supplemental disclosures of non-cash activities:
Issuance of commitment shares to Lincoln Park pursuant to agreement	$ 171,000