Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Redeemable convertible preferred stock (as converted to common stock)	Common Stock	Additional Paid-In-Capital	Accumulated Other Comprehensive Gain (Loss)	Accumulated Deficit	Total
Balance at beginning at Dec. 31, 2018	$ 124,728		$ 36,646		$ (86,565)	$ (49,919)
Balance at beginning (in shares) at Dec. 31, 2018	64,730,410	238,986
Stock-based compensation expense			215			215
Net loss					(5,362)	(5,362)
Balance at ending at Mar. 31, 2019	$ 124,728		36,861		(91,927)	(55,066)
Balance at ending (in shares) at Mar. 31, 2019	64,730,410	238,986
Balance at beginning at Dec. 31, 2018	$ 124,728		36,646		(86,565)	(49,919)
Balance at beginning (in shares) at Dec. 31, 2018	64,730,410	238,986
Net loss						(43,755)
Balance at ending at Dec. 31, 2019		$ 3	259,049	$ (6)	(130,320)	128,726
Balance at ending (in shares) at Dec. 31, 2019		28,567,837
Exercise of stock options			112			$ 112
Exercise of stock options (in shares)		103,385				103,385
Vesting of restricted common stock			30			$ 30
Stock-based compensation expense			1,238			1,238
Disgorgment of stockholders' short-swing profits, net			52			52
Net unrealizable gain on marketable securities				51		51
Net loss					(11,886)	(11,886)
Balance at ending at Mar. 31, 2020		$ 3	$ 260,481	$ 45	$ (142,206)	$ 118,323
Balance at ending (in shares) at Mar. 31, 2020		28,671,222