Condensed consolidated statements of cash flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net loss	$ (18,388)	$ (2,209)
Non-cash items:
Stock-based compensation	1,705	1,866
Depreciation and amortization	390	82
Loss on disposal of property and equipment	173
Amortization of operating lease right-of-use assets	531	52
Write-off of ROU asset upon lease termination	113
Unrealized foreign exchange loss (gain)	(21)	21
Changes in operating assets and liabilities:
Other current assets and other non-current assets	(870)	(246)
Accounts payable and accrued liabilities	1,230	(3,792)
Operating lease right-of-use assets	(169)
Operating lease liabilities	72
Net cash used in operating activities	(15,234)	(4,226)
Investing activities
Purchase of property and equipment	(1,079)
Net cash used in investing activities	(1,079)
Financing activities
Proceeds from exercise of stock options	3,695
Payment on finance lease obligations	(4)	(4)
Net cash provided by (used in) financing activities	3,691	(4)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	3	2
Net change in cash, cash equivalents and restricted cash during the period	(12,619)	(4,228)
Cash, cash equivalents and restricted cash, beginning of period	143,093	76,928
Cash, cash equivalents and restricted cash, end of period	130,474	72,700
Supplemental disclosure of non-cash investing and financing activities:
Offering costs unpaid at period-end	255
Purchases of property and equipment unpaid at period-end	405
Operating lease liabilities arising from obtaining ROU asset	$ 9,614	$ 515