Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating expenses:
Research and development	$ 10,464	$ 9,268	$ 20,483	$ 17,807
General and administrative	4,211	2,486	6,974	4,254
Impairment of acquired IPR&D				21,692
Impairment of goodwill	7,420		7,420
Depreciation and amortization	59	153	197	260
Total operating expenses	22,154	11,907	35,074	44,013
Loss from operations	(22,154)	(11,907)	(35,074)	(44,013)
Other income, net:
Interest income (expense), net	31	(113)	11	(217)
Foreign currency exchange gain	110	155	51	94
Tax credit income	115	277	1,079	1,201
Change in fair value of financial instruments	(41)	(6)	(118)	(62)
Total other income	215	313	1,023	1,016
Loss before income taxes	(21,939)	(11,594)	(34,051)	(42,997)
Income tax benefit				4,555
Net loss	$ (21,939)	$ (11,594)	$ (34,051)	$ (38,442)
Net loss per share:
Basic and diluted	$ (0.57)	$ (0.37)	$ (0.91)	$ (1.23)
Weighted average common shares outstanding:
Basic and diluted	38,440,647	31,433,494	37,235,209	31,376,425
Other comprehensive loss:
Gain (loss) on foreign currency translation	$ 91	$ (856)	$ (134)	$ (515)
Unrealized gain on short-term investments	120	37	146	13
Total comprehensive loss	$ (21,728)	$ (12,413)	$ (34,039)	$ (38,944)