Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating expenses:
Research and development	$ 10,019	$ 8,539
General and administrative	2,763	1,769
Impairment of acquired IPR&D		21,692
Depreciation and amortization	138	107
Total operating expenses	12,920	32,107
Loss from operations	(12,920)	(32,107)
Other income, net:
Interest expense, net	(20)	(104)
Foreign currency exchange loss	(59)	(61)
Tax credit income	964	924
Change in fair value of financial instruments	(77)	(56)
Total other income	808	703
Loss before income taxes	(12,112)	(31,404)
Income tax benefit		4,555
Net loss	$ (12,112)	$ (26,849)
Net loss per share:
Basic and diluted	$ (0.34)	$ (0.86)
Weighted average common shares outstanding:
Basic and diluted	36,016,406	31,318,746
Other comprehensive loss:
Gain (loss) on foreign currency translation	$ (225)	$ 341
Unrealized gain (loss) on short-term investments	26	(24)
Total comprehensive loss	$ (12,311)	$ (26,532)