Combined Statements of Operations and Comprehensive Loss (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Research and development expenses, related party	$ 207	$ 0	$ 207	$ 0
General and administrative expenses, related party	156	72	174	196
Interest expense, related party	(302)	(4)	(498)	(8)
Change in fair value of warrant liabilities, related party	(57,754)	0	(59,031)	0
Change in fair value of convertible promissory notes, related party	$ (732)	$ (18)	$ (1,053)	$ (22)