Net Income Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 15,773	$ 94,123
Net income attributable to Innoviva stockholders, diluted	$ 18,342	$ 95,327
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	69,544,000	101,365,000
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	116,000	70,000
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	93,730,000	113,624,000
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 0.23	$ 0.93
Diluted net income per share	$ 0.20	$ 0.84
2023 Notes
Numerator:
Add: interest expense on Notes	$ 1,021	$ 1,204
Denominator:
Dilutive effect	10,155,000	12,189,000
2025 Notes
Numerator:
Add: interest expense on Notes	$ 1,164	$ 0
Denominator:
Dilutive effect	11,150,000	0
2028 Notes
Numerator:
Add: interest expense on Notes	$ 384	$ 0
Denominator:
Dilutive effect	2,765	0