CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (4,172)	$ (3,597)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	625	339
Right-of-use asset amortization	(25)	199
Stock-based compensation	1,199	1,283
Other non-cash transactions	(41)	100
Changes in operating assets and liabilities	(9,724)	(13,455)
Net cash used in operating activities	(12,138)	(15,131)
Investing activities:
Purchases of property and equipment	(28)	(1,927)
Proceeds from maturity of investments	0	28,373
Purchases of investments	0	(26,032)
Net cash (used in)/provided by investing activities	(28)	414
Financing activities:
Proceeds from exercise of stock options	20	0
Issuance of common stock, net of issuance costs	9,673	0
Net cash provided by financing activities	9,693	0
Effect of exchange rate change on cash and cash equivalents	(1,128)	(112)
Net decrease in cash and cash equivalents	(3,601)	(14,829)
Cash and cash equivalents at beginning of period	70,436	62,260
Cash and cash equivalents at end of period	66,835	47,431
Supplemental cash flow disclosures:
Net unrealized gain on investments	0	46
Property and equipment included in accounts payable	$ 36	$ 590