Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Selected Quarterly Financial Data
Total revenues	$ 90,545	$ 91,592	$ 94,396	$ 74,877	$ 117,553	$ 113,739	$ 107,382	$ 104,061	$ 351,410	$ 442,735	$ 410,596
Total cost and expenses	59,054	65,956	69,419	63,857	79,964	73,716	1,190,521	43,964	258,286	1,388,165	160,259
Other income (expense), net	(7,496)	(8,267)	(6,101)	(6,062)	(7,229)	(8,091)	6,917	5,764	(27,926)	(2,639)	2,085
Net income (loss)	2,256	3,646	(860)	(4,162)	(1,745)	13,950	(1,089,478)	45,714	880	(1,031,559)	175,065
Net income (loss) attributable to Ironwood Pharmaceuticals, Inc.					(1,087)	15,321	(1,062,187)	45,714	880	(1,002,239)	175,065
Comprehensive income (loss) attributable to Ironwood Pharmaceuticals, Inc.	$ 5,231	$ 2,064	$ (408)	$ (2,053)	$ (3,303)	$ 14,569	$ (1,062,187)	$ 45,714	$ 4,834	$ (1,005,207)	$ 175,065
Net income (loss) per share - basic (in dollars per share)	$ 0.01	$ 0.02	$ (0.01)	$ (0.03)	$ (0.01)	$ 0.1	$ (6.84)	$ 0.3	$ 0.01	$ (6.45)	$ 1.13
Net income (loss) per share - diluted (in dollars per share)	$ 0.01	$ 0.02	$ (0.01)	$ (0.03)	$ (0.01)	$ 0.09	$ (6.84)	$ 0.25	$ 0.01	$ (6.45)	$ 0.96