CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (41,970)	$ (22,003)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,386	471
Depreciation and amortization expense	71	77
Loss on transfer of non-financial assets (Note 16)	4,004	0
Non-cash lease expense	416	0
Accretion of debt discount	584	80
Loss on extinguishment of debt	566	0
Change in fair value of preferred stock warrant liability	288	264
Change in fair value of derivative liability	(183)	411
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and research and development incentive receivable	290	631
Accounts payable	(3,131)	209
Accrued expenses	(595)	1,174
Lease liabilities	(540)
Net cash used in operating activities	(38,814)	(18,686)
Cash flows from investing activities:
Cash, cash equivalents and restricted cash acquired in connection with the Merger	26,406	0
Proceeds from transfer of non-financial assets	896
Acquisition of property, equipment and intangible assets	(91)	0
Net cash provided by investing activities	27,211	0
Cash flows from financing activities:
Proceeds from exercise of stock options and warrants	605	7
Proceeds from borrowings under loan and security agreements, net of issuance costs	9,849	0
Proceeds from issuance of Series B convertible preferred stock, net of issuance costs	0	4,461
Repurchase of Series Seed convertible preferred stock	0	(1,126)
Repayments of borrowings under loan and security agreement	(9,368)	(1,500)
Proceeds from sale of common stock and warrants, net of issuance costs	79,291	0
Net cash provided by financing activities	80,377	1,842
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(266)	0
Net increase (decrease) in cash, cash equivalents and restricted cash	68,508	(16,844)
Cash, cash equivalents and restricted cash at beginning of period	8,498	27,048
Cash, cash equivalents and restricted cash at end of period	77,006	10,204
Supplemental disclosure of non-cash investing and financing activities:
Acquisition of property, equipment and intangible assets included in accounts payable	38	0
Conversion of convertible preferred stock into common stock	64,675	0
Conversion of redeemable common stock into common stock	734	0
Conversion of convertible preferred stock warrants into common stock warrants	5,235	0
Fair value of net assets acquired in the Merger	$ 46,358	$ 0