CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Expenses:
Research and development	$ 8,872	$ 3,927
General and administrative	3,667	2,187
Loss from operations	(12,539)	(6,114)
Interest income	96	116
Other expense	(40)	(1)
Net loss	$ (12,483)	$ (5,999)
Per share information:
Net loss per share of common stock-basic and diluted (in dollars per share)	$ (0.24)	$ (0.15)
Basic and diluted weighted average shares outstanding (in shares)	52,465,207	40,373,083
Net loss	$ (12,483)	$ (5,999)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities	2	(11)
Total comprehensive loss	$ (12,481)	$ (6,010)