NET INCOME PER SHARE - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 179,722	$ 213,921	$ 265,854
Net income attributable to Innoviva stockholders, diluted	$ 191,304	$ 225,569	$ 270,590
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	65,435	69,644	82,062
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	149	108	59
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	86,876	95,248	94,310
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 2.75	$ 3.07	$ 3.24
Diluted net income per share	$ 2.2	$ 2.37	$ 2.87
2023 Notes
Numerator:
Add: interest expense on Notes, net of tax effect	$ 89	$ 2,439	$ 4,736
Denominator:
Dilutive effect	187	6,188	12,189
2025 Notes
Numerator:
Add: interest expense on Notes, net of tax effect	$ 5,116	$ 4,583	$ 0
Denominator:
Dilutive effect	11,150	11,150	0
2028 Notes
Numerator:
Add: interest expense on Notes, net of tax effect	$ 6,377	$ 4,626	$ 0
Denominator:
Dilutive effect	9,955	8,158	0