Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (52,091)	$ (33,285)
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion of liability related to sale of future royalties	4,385	4,075
Accretion of note payable discount and amortization of issuance costs	27
Depreciation and amortization	77	50
Stock-based compensation expense	4,984	3,872
Foreign currency adjustments	93	3,508
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,808	(1,662)
Other assets	171	(414)
Accounts payable	5	(393)
Accrued expenses	(5,313)	(2,272)
Other current and long-term liabilities	(1,008)	8
Net cash used in operating activities	(46,862)	(26,513)
Cash flows from investing activities:
Purchase of property, plant and equipment	(78)	(409)
Net cash used in investing activities	(78)	(409)
Cash flows from financing activities:
Proceeds from issuance of note payable, net of issuance costs	9,521
Proceeds from issuance of common stock, net of issuance costs	42,999	20,774
Proceeds from royalty agreement, net of issuance costs	14,750
Proceeds from exercise of options and vesting or RSUs	232	1,400
Net cash provided by financing activities	67,502	22,174
Effect of exchange rate changes on cash and cash equivalents	(385)	(1,415)
Net increase (decrease) in cash and cash equivalents	20,177	(6,163)
Cash and cash equivalents - beginning of period	131,843	163,885
Cash and cash equivalents - end of period	152,020	$ 157,722
Supplemental disclosures of cash and non-cash activities:
Warrants issued with long-term note payable	113
Deferred issuance costs included in accrued expenses	$ 34