Consolidated Statements of Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Total Stockholders’ Equity (Deficit) attributable to Millendo Therapeutics, Inc.	Total Equity Attributable to Noncontrolling Interests
Balance at beginning (in shares) at Dec. 31, 2018		13,357,999
Balance at beginning at Dec. 31, 2018	$ 73,122	$ 13	$ 234,876	$ (164,086)	$ 148	$ 70,951	$ 2,171
Stock-based compensation expense	939		939			939
Foreign currency translation adjustment	(9)				(9)	(9)
Net income (loss)	(10,366)			(10,366)		(10,366)
Balance at end (in shares) at Mar. 31, 2019		13,357,999
Balance at end at Mar. 31, 2019	63,686	$ 13	235,815	(174,452)	139	61,515	2,171
Balance at beginning (in shares) at Dec. 31, 2019		18,266,545
Balance at beginning at Dec. 31, 2019	59,871	$ 18	267,018	(208,654)	165	58,547	1,324
Issuance of common stock, net of issuance costs (in shares)		719,400
Issuance of common stock, net of issuance costs	5,650	$ 1	5,649			5,650
Exercise/forfeiture of BSPCE warrants (in shares)		12,307
Exercise/forfeiture of BSPCE warrants	78		593			593	(515)
Stock-based compensation expense	1,080		1,080			1,080
Foreign currency translation adjustment	(42)				(42)	(42)
Net income (loss)	(11,998)			(11,998)		(11,998)
Balance at end (in shares) at Mar. 31, 2020		18,998,252
Balance at end at Mar. 31, 2020	$ 54,639	$ 19	$ 274,340	$ (220,652)	$ 123	$ 53,830	$ 809