CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating expenses:
Research and development	$ 50,337	$ 22,894	$ 19,594
Selling, general, and administrative	28,080	9,518	6,311
Total operating expenses	78,417	32,412	25,905
Loss from operations	(78,417)	(32,412)	(25,905)
Other income (expense):
Revaluation of Series A Investor Instrument and Series A Investor Right/Obligation		(1,863)
Interest income, net	4,353	566	33
Total other income (expense):	4,353	(1,297)	33
Net loss and comprehensive loss	(74,064)	(33,709)	(25,872)
Net loss attributable to common stockholders	$ (74,064)	$ (37,582)	$ (29,074)
Net loss attributable to common stockholders per common share, basic and diluted	$ (2.39)	$ (2.83)	$ (2.85)
Weighted average common shares outstanding, basic and diluted	31,004,047	13,267,960	10,196,292