STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) $ in Thousands	Preferred Stock Series A Preferred Stock	Preferred Stock Series A-3 preferred stock	Preferred Stock Series B Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Series A Preferred Stock	Series B Preferred Stock	Total
Balance at the beginning at Dec. 31, 2017				$ 1	$ 85	$ 0	$ (24,498)			$ (24,412)
Balance at the beginning (in shares) at Dec. 31, 2017				1,369,212
Balance at the beginning at Dec. 31, 2017	$ 40,000		$ 0
Balance at the beginning (in shares) at Dec. 31, 2017	40,000,000		0
Increase (Decrease) in Stockholders' Deficit
Stock based compensation					263					263
Issuance of stock		$ 31,000	$ 91,223		4					4
Issuance of stock (in shares)		28,181,819	56,828,851	5,600
Net loss							(22,799)			(22,799)
Balance at the end at Dec. 31, 2018				$ 1	352		(47,297)			$ (46,944)
Balance at the end (in shares) at Dec. 31, 2018				1,374,812						1,374,812
Balance at the end at Dec. 31, 2018	$ 71,000		$ 91,223					$ 71,000	$ 91,223	$ 162,223
Balance at the end (in shares) at Dec. 31, 2018	68,181,819		56,828,851
Increase (Decrease) in Stockholders' Deficit
Stock based compensation					1,886					1,886
Issuance of stock					119					119
Issuance of stock (in shares)				125,109
Public offerings of common stock, net of issuance costs of $20.7 million				$ 10	237,965					237,975
Public offerings of common stock, net of issuance costs of $20.7 million (in shares)				10,438,770
Conversion of preferred stock to common stock	$ (71,000)		$ (91,223)	$ 16	162,207					162,223
Conversion of preferred stock to common stock (in shares)	(68,181,819)		(56,828,851)	15,560,569
Unrealized loss on marketable securities						(38)				(38)
Net loss							(33,737)			(33,737)
Balance at the end at Dec. 31, 2019				$ 27	$ 402,529	$ (38)	$ (81,034)			$ 321,484
Balance at the end (in shares) at Dec. 31, 2019				27,499,260						27,499,260
Balance at the end at Dec. 31, 2019	$ 0		$ 0
Balance at the end (in shares) at Dec. 31, 2019	0		0