Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating expenses:
Research and development	$ 7,308	$ 3,871	$ 19,493	$ 9,840
General and administrative	4,443	3,935	13,075	7,340
Loss from operations	11,751	7,806	32,568	17,180
Other expenses:
Interest expense (income), net	(238)	54	(866)	39
Other loss	119	31	167	100
Net loss	(11,632)	(7,891)	(31,869)	(17,319)
Net loss attributable to noncontrolling interest		355		676
Net loss attributable to common stockholders	$ (11,632)	$ (7,536)	$ (31,869)	$ (16,643)
Net loss per share of common stock, basic and diluted	$ (0.87)	$ (10.61)	$ (2.38)	$ (23.43)
Weighted-average shares of common stock outstanding, basic and diluted	13,420,614	710,390	13,386,381	710,390
Other comprehensive income (loss):
Foreign currency translation adjustment	$ (17)	$ 11	$ (25)	$ 58
Comprehensive loss	(11,649)	(7,525)	(31,894)	(16,585)
Comprehensive income attributable to noncontrolling interest		3		10
Comprehensive loss attributable to Millendo Therapeutics, Inc.	$ (11,649)	$ (7,528)	$ (31,894)	$ (16,595)