CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating expenses:
Research and development	$ 10,705	$ 5,971	$ 31,575	$ 16,241
Selling, general, and administrative	8,539	2,315	19,691	5,188
Total operating expenses	19,244	8,286	51,266	21,429
Loss from operations	(19,244)	(8,286)	(51,266)	(21,429)
Other income (expense):
Revaluation of Series A Investor Instrument and Series A Investor Right/Obligation		(1,781)		(1,863)
Interest income, net	1,558	51	2,709	114
Total other income (expense):	1,558	(1,730)	2,709	(1,749)
Net loss and comprehensive loss	(17,686)	(10,016)	(48,557)	(23,178)
Net loss attributable to common stockholders	$ (17,686)	$ (11,429)	$ (48,557)	$ (26,963)
Net loss attributable to common stockholders per common share, basic and diluted	$ (0.52)	$ (1.78)	$ (1.63)	$ (3.02)
Weighted average common shares outstanding, basic and diluted	34,256,519	6,404,254	29,859,314	8,918,389