CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss		$ (24,020)	$ (21,965)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense		1,645	1,459
Depreciation and amortization expense		127	133
Non-cash lease expense		385	366
Accretion of debt discount		225	198
Change in fair value of warrant liability		(5,439)	0
Other		(51)	(120)
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and research and development incentive receivable		2,084	1,633
Accounts payable		(1,714)	(713)
Accrued expenses		496	(984)
Lease liabilities		(250)	(236)
Net cash used in operating activities		(26,512)	(20,229)
Cash flows from investing activities:
Acquisition of property and equipment		(9)	(22)
Net cash used in investing activities		(9)	(22)
Cash flows from financing activities:
Employee taxes paid related to net share settlement of vested restricted stock units		0	(12)
Fees paid to amendment loan and security agreement and issuance costs related to the sale of warrants		(381)	(114)
Repayments of Secured Debt		(1,300)	(795)
Proceeds from sale of shares of common stock, and pre-funded warrants, net of issuance costs (1)	[1]		5,877
Payments for Repurchase of Common Stock	[1]	(443)
Net cash (used in) provided by financing activities		(2,124)	4,956
Effect of exchange rate changes on cash, cash equivalents and restricted cash		50	(69)
Net decrease in cash, cash equivalents and restricted cash		(28,595)	(15,364)
Cash, cash equivalents and restricted cash at beginning of period		123,028	83,108
Cash, cash equivalents and restricted cash at end of period		$ 94,433	$ 67,744

[1] (1) For the three month period ended March 31, 2023, includes payment of issuance costs related to December 2022 public sale of shares of common stock and pre-funded warrants