Net Income Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net income attributable to Innoviva stockholders, basic	$ 265,523	$ 72,438	$ 282,235	$ 255,509
Net income attributable to Innoviva stockholders, diluted	$ 268,698	$ 73,624	$ 291,633	$ 259,062
Denominator:
Weighted-average shares used to compute basic net income per share attributable to Innoviva stockholders	69,731	69,458	69,640	86,298
Dilutive effect of options and awards granted under equity incentive plan and employee stock purchase plan	128	52	94	49
Weighted-average shares used to compute diluted net income per share attributable to Innoviva stockholders	95,830	81,699	95,072	98,536
Net income per share attributable to Innoviva stockholders
Basic net income per share	$ 3.81	$ 1.04	$ 4.05	$ 2.96
Diluted net income per share	$ 2.80	$ 0.90	$ 3.07	$ 2.63
2023 Notes
Numerator:
Add: interest expense on Notes	$ 412	$ 1,186	$ 2,003	$ 3,553
Denominator:
Dilutive effect	4,866	12,189	6,629	12,189
2025 Notes
Numerator:
Add: interest expense on Notes	$ 994	$ 0	$ 3,533	$ 0
Denominator:
Dilutive effect	11,150	0	11,150	0
2028 Notes
Numerator:
Add: interest expense on Notes	$ 1,769	$ 0	$ 3,862	$ 0
Denominator:
Dilutive effect	9,955	0	7,559	0