Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net loss	$ (14,950)	$ (8,642)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,420	683
Depreciation and amortization	247	171
Amortization of operating lease right-of-use assets	265	528
Unrealized foreign exchange (gain)/loss	0	(14)
Changes in operating assets and liabilities:
Other current assets and other non-current assets	(813)	266
Accounts payable and accrued liabilities	(631)	878
Operating lease right-of-use assets	0	(169)
Operating lease liabilities	104	(141)
Net cash used in operating activities	(13,358)	(6,440)
Investing activities
Purchase of property and equipment	(1,089)	(107)
Net cash used in investing activities	(1,089)	(107)
Financing activities
Proceeds from exercise of stock options	282	3,392
Payment on finance lease obligations	0	(2)
Net cash provided by financing activities	282	3,390
Effect of exchange rate changes on cash, cash equivalents and restricted cash	0	(11)
Net change in cash, cash equivalents and restricted cash during the period	(14,165)	(3,168)
Cash, cash equivalents and restricted cash, beginning of period	193,434	143,093
Cash, cash equivalents and restricted cash, end of period	179,269	139,925
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property and equipment unpaid at period-end	794	0
Operating lease liabilities arising from obtaining ROU asset	$ 1,584	$ 9,614