Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities:
Net loss	$ (31,869)	$ (17,319)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	52	23
Stock-based compensation expense	3,130	759
Write-off of deferred financing costs		871
Non-cash interest		59
Amortization of operating lease right-of-use assets	(352)
Unrealized foreign currency loss		98
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(397)	(847)
Other assets	297
Accounts payable	812	67
Accrued expenses and other liabilities	(1,204)	1,868
Cash used in operating activities	(29,531)	(14,421)
Investing activities:
Purchase of property and equipment	(364)	(20)
Proceeds from sale of marketable securities	4,385
Net cash paid in Alize asset purchase		(524)
Cash provided by (used in) investing activities	4,021	(544)
Financing activities:
Repayment of debt	(134)	(125)
Payment of financing costs	(245)	(741)
Proceeds from convertible promissory notes		8,000
Proceeds from option and BSPCE warrant exercises	471
Repayment of principal on finance lease	(9)
Cash provided by (used in) financing activities	83	7,134
Effect of foreign currency exchange rate changes on cash	5	(24)
Net decrease in cash, cash equivalents and restricted cash	(25,422)	(7,855)
Cash, cash equivalents and restricted cash at beginning of period	73,770	17,623
Cash, cash equivalents and restricted cash at end of period	48,348	9,768
Supplemental schedule of non-cash investing and financing activities:
Right-of-use assets acquired under operating leases	$ 3,414
Financing costs in accounts payable and accrued expenses		$ 729