Net Income Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 1,280	$ 939	$ 36,145	$ 16,712
Net income attributable to Innoviva stockholders, diluted	$ 1,280	$ 4,593	$ 40,820	$ 22,935
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	65,341	69,643	66,557	69,594
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	148	39	137	77
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	65,489	95,653	88,175	94,692
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 0.02	$ 0.01	$ 0.54	$ 0.24
Diluted net income per share	$ 0.02	$ 0.05	$ 0.46	$ 0.24
2023 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 0	$ 570	$ 71	$ 1,591
Denominator:
Dilutive effect	0	4,866	376	7,511
2025 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 0	$ 1,375	$ 2,050	$ 2,539
Denominator:
Dilutive effect	0	11,150	11,150	11,150
2028 Notes
Numerator:
Add: interest expense on 2025 Notes, net of tax effect	$ 0	$ 1,709	$ 2,554	$ 2,093
Denominator:
Dilutive effect	0	9,955	9,955	6,360