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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 939	$ 88,948	$ 16,712	$ 183,071
Net income attributable to Innoviva stockholders, diluted	$ 4,593	$ 90,111	$ 22,935	$ 185,438
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	69,643	88,423	69,594	94,858
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	39	27	77	49
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	95,653	100,639	94,692	107,096
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 0.01	$ 1.01	$ 0.24	$ 1.93
Diluted net income per share	$ 0.05	$ 0.90	$ 0.24	$ 1.73
2023 Notes
Numerator:
Add: interest expense on Notes	$ 570	$ 1,163	$ 1,591	$ 2,367
Denominator:
Dilutive effect	4,866	12,189	7,511	12,189
2025 Notes
Numerator:
Add: interest expense on Notes	$ 1,375	$ 0	$ 2,539	$ 0
Denominator:
Dilutive effect	11,150	0	11,150	0
2028 Notes
Numerator:
Add: interest expense on Notes	$ 1,709	$ 0	$ 2,093	$ 0
Denominator:
Dilutive effect	9,955	0	6,360	0